In the view of her many admirers, she thrust a strike-infested half-pace Britain back among the front-runners in the commanding peaks of the industrial nations of the world.
Her detractors, many of them just as vociferous, saw her as the personification of an uncaring new political philosophy known by both sides as Thatcherism.
Tireless, fearless, unshakeable and always in command, she was Britain's first woman Prime Minister - and the first leader to win three General Elections in a row.
Mrs Thatcher, who became Baroness Thatcher, resigned as Prime Minister in November 1990 after a year in which her fortunes plummeted.
It was a year in which she faced a series of damaging resignations from the Cabinet, her own political judgments were publicly denounced by her own colleagues, catastrophic by-election humiliations, internal party strife, and a sense in the country that people had had enough of her after 11 years in power.
But history will almost certainly proclaim her as one of the greatest British peacetime leaders.
Her supporters believe she put the drive back into the British people.
And as she transformed the nation - attempting to release the grip of the state on massive industries and public services alike - she strode the earth as one of the most influential, talked-about, listened-to and dominant statesmen of the Western world.
When Argentina invaded the Falklands, she despatched a task force to the South Atlantic which drove the enemy off the islands in an incomparable military operation 8,000 miles from home.
She successfully defied Arthur Scargill's nationwide and year-long miners' strike, which threatened to cripple Britain's entire economic base.
Her triumphant achievement of power in May 1979 signalled the end of the era when trade union leaders trooped in and out of 10, Downing Street, haggling and bargaining with her Labour predecessors.
Instead she stripped the unions of many of their powers with the aim of transferring them to managements and individual consumers.
Within weeks of her arrival in Downing Street, foreign correspondents from all points of the globe - absent for so long from the House of Commons - flocked back to the press gallery. It was a sure sign that the world was sitting up and listening once again to what Britain had to say.
Whether you liked Mrs Thatcher or loathed her - and her Tory predecessor Edward Heath hated her beyond belief - whether you agreed with her or found her policies utterly repugnant, you could not deny her energy and drive.
Even many political foes secretly admired this single-minded woman, who never contemplated defeat and for whom all issues were black and white, not hedged about with grey.
Even - indeed particularly - her most bitter political enemies were forced to praise her crusading clarity of purpose and her determination, in their eyes, to serve "her people".
Veteran left winger Tony Benn frequently held her up as an example of how a great political party should be led, comparing her with what he regarded as Neil Kinnock's fudged leadership of the Labour Party.
Margaret Thatcher towered above all other political figures in Britain and her dominance of the Cabinet was supreme and rarely challenged. She was the equal of statesmen across the world. She elevated Downing Street to something like the status of the White House and the Kremlin, symbols of the then two great superpowers. Nobody talked down to her.
Yet the Iron Lady - a title bestowed upon her by her enemies in Moscow, which, incidentally she relished - was not all stern, steely and strident. She was delightful with children and she could not disguise her glee - "We are a grandmother" - when her grandson Michael was born in Dallas in February, 1989.
She regularly and touchingly admitted that she could not do her job properly without the unfailing and unstinting support of her "marvellous" husband, Denis. He was, she said, the "golden thread" running through her life. His death, in June 2003, some weeks after major heart surgery, was a profound blow to her.
Sir Denis, as he became after she left Downing Street, was constantly at her side, an impeccable consort, protecting her and guiding her in all weathers and in all parts of the world.
He was a wonderful source of encouragement and comfort to her when, as sometimes happened, she returned home in tears after a particularly gruelling day. He made no attempt to disguise his contempt for those who opposed his wife, but he never got involved publicly in policy or political discussions.
His death came at a time when Margaret Thatcher's own health - she was ten years younger than him - was the subject of speculation. She had suffered a series of strokes and her doctors had forbidden her to make any more speeches - instructions which she was occasionally known to breach.
Sir Denis's death was a massive blow to Lady Thatcher. But there was more grim trouble ahead.
Her son, Sir Mark - he inherited the baronetcy from his father - was charged in South Africa in connection with a plot to overthrow the Government of oil-rich Equatorial Guinea. The charge carried a maximum penalty of 15 years, and possible death if Sir Mark was extradited to Equatorial Guinea.
The news broke when Lady Thatcher was on holiday in the United States. She doted on her son and the charge plainly devastated her.
However, after weeks under house arrest in Capetown, where he lived, Mark in January 2005, pleaded guilty to unwittingly helping to finance a foiled coup plot in oil-rich Equatorial Guinea. He accepted a three million rand fine and a suspended jail sentence.
Judge Abe Motala told him to pay the fine as part of the plea deal, but if he failed to do so by January 17 that year, he faced a five-year prison sentence with a further four years suspended for five years.
Meanwhile his wife Diane and their two children had returned to Dallas, and he planned to rejoin them immediately. However his conviction led to problems about his entry into the United States and instead he returned to London to stay with his mother.
For her it was a massive relief that her son avoided a long prison sentence and also, more traumatically, avoided what could have resulted in a fatal extradition to Equatorial Guinea.
Thatcher always conceded, too, that personal attacks on her, and particularly on members of her family, wounded her deeply. And yet the woman who took on Argentina and who had the people of Moscow reaching out and yearning to touch her, could not bear the sight of creepy-crawlies or snakes.
Mrs Thatcher was obsessively British, batting for Britain wherever she went, wearing exquisite home-produced clothes, upbraiding those who did not, and turning up her nose at the French Perrier Water. "What's wrong with British water?" she demanded.
Her dramatic downfall came about during the second of two challenges to her leadership. She realised that if she stayed on to take her challenger Michael Heseltine - a man she disliked intensely, personally and politically - into a second ballot, he would almost certainly supplant her. That was a prospect she could not bear to see happen.
And so, after consulting her Cabinet colleagues, one by one, she decided she must go, and tearfully gave the Cabinet the news the following morning.
By doing so, she paved the way for one of her favourite "sons" John Major to follow her into 10, Downing Street. But her support for him was luke-warm. She was to say later that she backed him because he was "the best of a poor bunch".
She marked her decision to quit with the historic expression: "It's a funny old world" - pointing out that she had been summarily removed from power even though she had won every election she had fought.
Some of her friends believed that her decision to go to Paris, rather than remain in Westminster, during that first fateful ballot, demonstrated an arrogance and a misjudgment which may well have cost her those crucial handful of votes which would have kept her in Downing Street. If she had received just four more votes, there would have been no need for a second ballot.
But there was no let-up in her energetic activities once she arrived in the House of Lords. She remained a ferocious critic of the European Union, and led a crusade in the Upper House against the Maastricht Treaty.
She was accused, as well, of attacking her successor, John Major, in the same way that her predecessor, Sir Edward Heath, had constantly criticised her when she was in power. But her strictures on John Major did not carry the bitterness and resentment of Heath's criticisms of her.
Years later, she was to be praised by two Labour Prime Ministers, Tony Blair and Gordon Brown, both of whom invited her into Downing Street soon after they came to power. These were events which enraged some factions in the Labour Party.
Baroness Thatcher maintained a gruelling programme of lecture tours worldwide, showing little, if any, sign of slowing down her scorching pace. But there were moments when her stamina and health came into question.
Once, in 1994, she collapsed in the middle of a speech in Santiago, Chile. but she shrugged off warnings from her friends that she should start to take things more easily.
And later that year, her friends were shocked at her gaunt and haggard aspect, three days before her 69th birthday, when she made a token appearance on the platform of the Tory Party conference in Bournemouth.
Her response to that renewed expression of alarm among her supporters was to dash off on another exhausting global speaking tour.
But there was little doubt that her health was affected by the combination of a massive four-hour dental operation, an enforced diet, and worry about reports of her son Mark's alleged profiteering from Middle East arms deals she had negotiated as Prime Minister, as well as the apparently impending break-up of his marriage. But those reports came to nothing.
But neither age nor anything else was going to stop this woman from expressing herself vigorously and passionately whenever she felt the need. In 1997, she derided the British Airways decision to introduce "modern art" on the tailfins of their fleet instead of the symbol of the Union Flag.
She famously covered one of these offending tailfins on the model of an aircraft with a handkerchief while touring the stalls at the Tory Party conference.
And in October, 1998 she called for the immediate release of ex-President Pinochet of Chile, who was being held to face an extradition request by Spain for alleged murder.
Baroness Thatcher said he saved many British lives during the Falklands conflict, that Chile was "a good friend to this country" and that Pinochet must be allowed to return to his own country forthwith.
She caused a stir by visiting the former Chilean leader while he was effectively under house arrest near London, and having lunch with him. But her appeals to the then Home Secretary Jack Straw were ignored.
Before that, in a last-minute move, she backed the Tory leadership campaign of William Hague, support which may have helped him to defeat his rivals by an unexpectedly large margin.
Margaret Hilda Roberts was born in 1925 in the Lincolnshire town of Grantham. She quickly had the virtues of thrift, hard work, morality and patriotism drilled into her by her beloved father Alderman Alfred Roberts, who ran two grocers' shops and a post-office, and became mayor of the town in 1943.
Alderman Roberts was a devout Methodist, a lay preacher and a proudly self-made man. Margaret never forgot - and throughout her career never tired of quoting - his words to her: "You'll never get anywhere if you don't work, girl."
Not only that, but she acted on it. For it was her colossal industry, her almost innocent belief that all her objectives not only could but would be achieved which launched her into a political career unsurpassed by any woman before her - and precious few men as well.
Her associates at school and university - she had few close friends - recall her as industrious, serious-minded, and soberly-dressed, but also possessing what one of them has since described as "an irritating sense of her own superiority".
Inevitably she became head girl at Kesteven and Grantham Girls' High School. She went on a bursary to Somerville College, Oxford, where she read chemistry.
Her principal at Oxford fell short of wild enthusiasm for her abilities, describing her as "a perfectly good second-class scientist".
However, she went on to become only the third woman president of the University's Conservative Association. She continued to work as a chemist until 1954 when she switched to become a barrister specialising in tax cases.
It was in this part of her career that she demonstrated her formidable ability to master a brief and to shame those who had not bothered to do so.
And it was the kind of training which years later made her virtually invulnerable at Question Time in the House of Commons. No matter what subject, however abstruse, was pitched at her, and without previous notice, she dealt with it with total command.
In 1951 she married Denis Thatcher, a shrewd and highly successful industrialist some ten years her senior. Contrary to common belief, Mrs Thatcher never dominated that marriage. Denis, an independent character, carried on with his business life while she pursued her political career.
In a very loving partnership he was intensely proud of her achievements and she was no less touched by his unswerving loyalty to her, his impeccable performance as her consort on official occasions, and his instinctive protectiveness towards her.
That instinct was demonstrated more than once when she faced peril in either over-friendly or faintly menacing crowds surrounding her during her street walkabouts, in scores of countries round the world, particularly in Australia and Turkey.
Mrs Thatcher launched into her battle to get into Parliament by unsuccessfully fighting Dartford - where she met Denis - in 1950 and again in 1951. Their twins, Mark and Carol, were born by Caesarean operation.
She finally entered the Commons in 1959 as Member for Finchley, a seat she represented throughout her career as an MP. The smartly-dressed, brisk and businesslike blonde did not remain unnoticed for long.
She swiftly adapted to the strange ways of Westminster. Her friendly manner and warmth belied and disguised the white heat of her ambition.
Thatcher epitomised then, as she did throughout her career, the self-made woman. Once she said contemptuously: "I owe nothing to Women's Lib" when she was criticised by feminists.
In the final years of the Harold Macmillan-Alec Douglas-Home administrations, Mrs Thatcher was parliamentary secretary, Ministry of Pensions and National Insurance.
Later, Mr Heath, the man she was destined to topple from the Tory leadership, took her into his shadow cabinet in 1966, but not without what turned out to be fateful reservations. He observed uncannily: "Once she's there, we'll never be able to get rid of her."
A quarter of a century later Mr Heath was still brooding moodily over those words.
When the Heath administration took office in 1970, Mrs Thatcher became Education Secretary, a key job in the new cabinet. Here, she worked uneasily. Her natural desire to give people independence and self-reliance was constrained - and had to be - by the collective approach of a Government much more timid than her own administrations were to be.
Even so, she quickly became a hate figure on the Labour benches, branded as "Thatcher the Milk Snatcher" because of her decision to stop free milk for primary schoolchildren.
She also cancelled a Labour circular requesting councils to move towards comprehensive schooling and she attempted to reform student union financing.
She was fast becoming a substantial figure in the Tory hierarchy. People were sitting up and taking notice - and some of her colleagues were already looking decidedly uneasy at the prospect of this by now clearly insatiable political ambition.
The two disasters that befell the Conservatives - general election defeats in February and October 1974 under the uninspiring leadership of Mr Heath - gave Mrs Thatcher the opportunity she so desperately sought.
There was now widespread dissatisfaction with Mr Heath. After that second defeat he sat, crunched up to half his size, a pitiable figure, waiting on a hard wooden bench in the committee corridor of the House of Commons to be told bluntly by the powerful Tory 1922 Committee of backbenchers just what they thought of him.
The word quickly went around that Mrs Thatcher would be bold enough to challenge him. She first consulted her close friend, confidant and even guru, Sir Keith, later Lord Joseph, and was assured that he would not stand. She would never have challenged Heath if Joseph had decided to enter the fray. But he did not.
Opportunities like that come once in a political lifetime. If you miss them, you have missed everything. Mrs Thatcher hurled down the gauntlet - and from that moment Heath was a beaten, resentful and doomed man.
It is arguable that if she had not been so intrepid, none of her timid colleagues would have dared to challenge him. Indeed some waited until she had smashed Heath out of the running before plucking up the courage to enter the fray themselves.
But by now she was the darling of Tory rank-and-file MPs sickened by what they regarded as the wishy-washy Heath brand of Conservatism. They were struck with admiration at her valour.
She made short work of defeating the lugubrious, lovable Willie Whitelaw - he wept when he was beaten - who epitomised languor and lethargy. And so, in 1975 she became the first woman at the helm of the Conservative Party, hell-bent on seeing the Tories back in power.
Her principal lieutenant in that leadership election campaign was Airey Neave, who was tragically assassinated by the IRA in March, 1979, only months before she came to power.
She was shattered by the news, but his death served only to increase her resolution to crush terrorism, to offer terrorists no quarter, to do no deals with them. She regarded them as vicious criminals, not political partisans.
Later, Mrs Thatcher was to tell a press conference in Saudi Arabia, when questioned about "political" reasons for IRA activity: "A crime is a crime is a crime."
She denounced those who gave the terrorists, in her own striking phrase, "the oxygen of publicity".
So Mrs Thatcher drove in triumph that night in 1975 from the House of Commons to Conservative Central Office where she straightaway set in train an unstoppable campaign whose momentum, four years later, was to pitch her into power.
First Harold Wilson and then his successor James Callaghan quickly found they had a sweetly snarling tigress to deal with at the Despatch Box, compared with the lumbering bear that was Edward Heath.
She injected new heart, spirit and fire into the Conservative Party. Meanwhile Labour staggered from one crisis to another, winding up with the so-called 1978-79 winter of discontent, during which strikers even refused to bury the dead and with the Government seemingly impotent to act.
To crown it all Callaghan returned to the grime and snow of strike-ravaged Britain from an indulgent summit in the tropical sunshine of Guadeloupe and was reported as saying: "Crisis? What crisis?"
The words were, in fact, a headline in the following day's Sun newspaper. But from that moment on he, too, was a doomed man.
Within months, Mrs Thatcher, aged 53, was stepping into Downing Street, softly quoting from memory the exquisite prayer of St Francis of Assisi: "Where there is discord, may we bring harmony. Where there is error, may we bring truth. Where there is doubt, may we bring faith. Where there is despair, may we bring hope."
She had belied her prediction seven years earlier, when questioned about the likelihood of there being a woman Prime Minister. She had said then: "I don't think it will come for many, many years. I don't think it will come in my lifetime."
Mrs Thatcher set to work with fervour. As inflation continued to rise, she served notice of the strict monetary policy which she was never to betray.
The state was to be "rolled back" in a huge programme of privatisation. Trade union power was to be curbed and new laws introduced to make it harder to go on strike.
Among her first major achievements was to settle the Rhodesia crisis which had been lingering unresolved since the mid-1960s.
Lord Soames went out to Rhodesia and within months - after years of vain negotiations, mainly by Labour - it was ironically a Conservative Government in Britain which helped install a Marxist administration under Robert Mugabe in the newly-renamed Zimbabwe. Mugabe was not the favoured choice, but she had ended a 13-year crisis, even though Mugabe's victory would, years later, produce a different but no less savage crisis for Zimbabwe and in particular its white population.
She also quickly made her presence felt with foreign leaders. Mrs Thatcher had a nervous habit, particularly with strangers, of so dominating a conversation that the other party could rarely get a word in.
The former Irish Prime Minister Jack Lynch said with feeling after prolonged negotiations with her in Dublin: "It was adamant, persistent and if I may say so very repetitive."
Mrs Thatcher quickly wanted to divest the unions of power. But Employment Secretary James Prior, a voluble but nervous man, amazingly sold her the idea of caution and doing everything "step by step".
She succumbed reluctantly to his reasoning, but this was only the first of a series of screaming rows the pair of them had.
`Unnamed sources' always said that she treated her colleagues - and civil servants - abominably. That was never true. She relished a fight, she usually won, but was courteous in all her personal encounters.
But she respected - and listened to - those of her colleagues who stood up to her. After she left power, volume after volume of political memoirs, from embittered and angry former Cabinet Ministers in her administrations, described fearsome storms within the Cabinet and without.
Significantly she never had a woman in her Cabinet who wielded any influence of any consequence. Baroness Young was the only woman to reach her Cabinet, and then only briefly, as Leader of the House of Lords: a post which carried virtually no authority within the Government.
Thatcher could not handle women, but shamelessly exploited her feminine wiles as well as her innate dominance to succumb or win over her male Cabinet colleagues.
Once she described herself as "the strongest man" in her Cabinet. Her inability to do business with women was graphically demonstrated when she had talks in Delhi with Indira Gandhi, who was later to be assassinated.
The Indian leader also found it virtually impossible to negotiate with another woman as powerful and clever as herself. When they emerged from a private meeting, the sparks fairly flew off both of them.
From the moment Thatcher ousted him from the leadership, Mr Heath remained embittered, resentful and sometimes unapproachable.
Every so often he would raise his head and explode into rancour. But his unwillingness to face the fact of his defeat quickly lost him friends.
Meanwhile, Mrs Thatcher, now proclaimed as some kind of dragon-slaying St George, marched upward and onward. She rejected demands for increased public spending in the face of world recession, stood firm against bloody inner city riots, and refused to bow to IRA threats over hunger strikers.
She defended her decision not to recommend honours for Britain's Moscow Olympic team - the athletes had taken part against her wishes - in view of the human rights situation in Russia and the Soviet invasion of Afghanistan.
But later she was to relent partially by making one of the "transgressors", athlete Colin Moynihan, a junior minister in one of her subsequent administrations.
She had epitomised her style, some say her obstinacy, when she told the Tory Party conference in 1980: "To those waiting with bated breath for that favourite media catch-phrase, the U-turn, I have only one thing to say, you turn if you want to. The lady's not for turning."
That phrase, greeted with uproarious cheers, lived on down the ages, and perfectly summed up the woman in a handful of words.
When President Reagan arrived on the scene there was an instant rapport, a close and abiding friendship which endured long after he left office and continued until his death. She remained friendly with his widow, Nancy and the two met from time to time.
The warmth between Reagan and Thatcher was remarkable and during that period the "special relationship" between Britain and the United States was very special indeed.
But there was one serious disagreement between them. On October, 1983, US forces invaded the Caribbean island of Grenada to overthrow the ultra-leftists who had just seized power.
Thatcher was incandescent that this invasion had taken place on a Commonwealth country, whose nominal head of state was the Queen, without any consultation. It was to be the only blot on an otherwise unflawed political relationship.
Her most formidable test was to come in 1982 when Argentina invaded the Falklands, hoping that Britain would not bother to attempt the massive long-distance operation of reclaiming them. The Argentine dictator General Galtieri had grossly underestimated the lady.
A huge and majestic task force was soon under sail, speeding south armed to the teeth, and determined to liberate the Falkland Islanders. While the bloody conflict raged on - one `of the great military achievements of modern times' - Mrs Thatcher wore nothing but black.
She was sombre and near-ecstatic in turn as the news from the front plunged and soared as each day passed. It was "our boys" at the front, and when South Georgia was recaptured by the Royal Marines midway through the conflict she stood outside Downing Street and said: "We should rejoice at that news."
To mount the task force was itself a calculated gamble. Not even her top military advisers could guarantee success. But typically she went ahead, outwardly proclaiming that nothing but triumph was possible.
And afterwards, announcing the ceasefire to a joyous nation, she proclaimed: "We knew what we had to do and we went about it and did it. Great Britain is great again."
No wonder, therefore, after the invaders had been driven off, that Mrs Thatcher received a tumultuous reception when she visited the Falklands the following January. Then and thereafter she would never compromise the sovereignty of the Falkland Islands. She would negotiate with Argentina on everything but sovereignty.
And no wonder, too, when she went to the country in 1983 - in what she denied was a khaki election - the nation swept her back to power with an overall majority of more than 140. Hers was the kind of leadership Britain had not seen since the days of war.
But she was helped on her way by a tattered and disillusioned Labour Party by now in disarray, torn apart by the birth of the SDP, bedevilled by internal strife and personal bickering, and led by Michael Foot, an old and stumbling man who was clearly no match for Mrs Thatcher.
But this was not before she had virtually publicly rebuked Francis Pym, who had been Foreign Secretary during the Falklands conflict, for suggesting, during the campaign, that democracy would be served better if the Tories had only a small Commons majority. Mrs Thatcher was outraged by this remark, and wasted little time after the election to dump him. His political career swiftly drew to a close, although he was subsequently to prove an irritant to her on the back-benches.
Before long the miners' strike was upon her. The miners had succeeded in toppling Mr Heath in 1974. Mrs Thatcher was made of sterner stuff.
The Government's policy was "no surrender", while Arthur Scargill, day after day, ran rings round the blundering National Coal Board chairman, Sir Ian MacGregor, to the exasperation of Mrs Thatcher.
The strike, one of the most bitter and bloody to hit Britain, surged on for a year, with scenes of violent clashes between mounted police and pickets almost a nightly feature on TV screens. Neil Kinnock, by now the Labour leader, seemed afraid to condemn either one side or the other.
But Mrs Thatcher knew where to stand. And after almost precisely a year the strike fizzled out, the miners dejected and broken and with feelings of hate likely to linger for decades in Britain's coalfields communities between those who supported and those who opposed Arthur Scargill.
That dispute was followed by the hardly less vicious News International Wapping battle, when Rupert Murdoch abruptly sacked his printers and left Fleet Street. Violent demonstrations became a Saturday-night commonplace, but they, too, stopped after a year.
There was to be no "tinkering" with privatisation as in the Heath era when a few pubs in Carlisle and Thomas Cook's were taken out of public hands. She privatised water, electricity, gas, telecommunications, and whatever else came to hand. "If it moves, privatise it," became the Government's motto.
Local authorities were forced to use private companies for many of their services. She was determined to weaken the power of the state and of the official in Whitehall and town hall alike.
It was after the 1983 election that the Cecil Parkinson affair blew up. It was he as Tory chairman who had master-minded the 1983 election landslide and it was now his admitted affair with his secretary Sara Keays which so embarrassed Mrs Thatcher, a consistent proclaimer of the virtues of family life.
The affair overshadowed the 1983 Tory Conference in Blackpool, and virtually ruined what was to have been a spectacular victory rally.
Reluctantly, she had no option but to relieve him of his Cabinet post as Trade and Industry Secretary. His extra-marital activities had driven a coach and horses through her family policy.
But his enforced departure she regarded as an immense loss to the Cabinet, and - as she promised at the time of his resignation - she restored him to office after the 1987 general election.
Mrs Thatcher's narrowest escape came in the 1984 Brighton bombing when the IRA just failed to assassinate her with an explosion which shattered the seafront Grand Hotel, temporary home for most of the Cabinet during the Tory Party conference.
She had left the bathroom in her hotel suite only seconds before the bomb destroyed it.
Despite the deaths of her close friends and injuries to others, and the shock to herself, the conference went ahead the following morning when she defiantly told delegates: "It was an attempt not only to disrupt and terminate our conference, it was an attempt to cripple Her Majesty's democratically-elected Government.
"That is the scale of the outrage in which we have all shared. And the fact we are gathered here, now, shocked but composed and determined, is a sign not only that this attack has failed, but that all attempts to destroy democracy by terrorism will fail."
A few days later, in a moving comment, she described being in church the following Sunday, with the sun's rays beaming on the flowers. She said: "This is a day I was not meant to see."
Mrs Thatcher, unbowed, marched ahead. With inflation now seemingly under control, and relations with Ireland improving by the signing of the nevertheless contentious Anglo-Irish Agreement, there seemed nothing in her way.
It was in 1984, also, that she stirred up massive trade union anger by banning union membership at GCHQ, the Government Communications Headquarters in Cheltenham. The activities of trade unions at GCHQ had caused concern in Washington. Union membership was restored to GCHQ as one of the first acts of the Blair Labour Government in 1997.
It was in 1985, that the storm over the book Spycatcher erupted. This was written by a former MI5 operative, Peter Wright and purported to expose a catalogue of abuses by the secret services which, he said, had "bugged and burgled our way across London".
Mrs Thatcher tried to stop publication throughout the world. But even efforts to ban it in Britain also eventually failed, at which point she introduced legislation imposing an "obligation of confidentiality" on retired members of the security services.
Then, late in 1985 another crisis suddenly hit her - the Westland Helicopter affair. This was a row over a small helicopter company which grew on a scale which, unbelievably, came close to destroying the Government itself.
It erupted into a scarcely-disguised internal Cabinet battle between Michael Heseltine, Defence Secretary, and Leon Brittan, Trade and Industry Secretary.
With the leaking to the Press Association early in January, 1986, of damning but selective parts of a letter written to Mr Heseltine by the then Solicitor-General, Sir Patrick Mayhew, the affair assumed a grotesque importance out of all proportion to the size of the helicopter company involved.
Both Heseltine, dramatically - by storming out of the Cabinet room - and later Brittan, more formally, quit the Cabinet. It was a savage blow to Mrs Thatcher and a sign to the outside world that all was not well within the Government.
Meanwhile, the Prime Minister was travelling around the world in high-speed convoys which allowed no time for idle sightseeing. Wherever she went she not only batted for Britain but - and particularly behind the Iron Curtain - shamelessly preached to Communists in particular the virtues of Thatcherism.
Her rapport with the Soviet leader Mr Gorbachev was, in a different way, as warm as that with President Reagan. They both enjoyed each other's debating. "I can do business with him," she once famously declared.
And on one occasion in the Kremlin, they talked for nine hours on end - to such an extent that she did not have time to change for a state banquet in the Kremlin that night.
On the streets of Moscow, Warsaw, Budapest, Peking, Nairobi, Lagos, Kuala Lumpur, Bombay, Jakarta, and New York, in fact wherever she went, the crowds poured out to greet her, stretching out to touch her, kissing her hand and her face.
The adulation world-wide was remarkable. In more than one country, Poland and the former Czechoslovakia to name but two, serious journalists asked her at news conferences whether she would take over their ramshackle governments. This was the kind of irresistible - but not bogus - flattery which she revelled in.
Her line towards the Common Market remained firm: loyal support but fiercely against any idea of a United States of Europe. She was accused by Mr Heath of megaphone and foghorn diplomacy, shouting at the Europeans and others when quieter dialogue would - in his opinion - have been more appropriate and more effective.
She would probably have agreed. But politicians the world over were used to being "handbagged" by Mrs Thatcher. They had come to expect no less. Mrs Thatcher never did anything behind cupped hands or in a whisper.
She went to the country again in 1987 on the advice of her party chairman, Mr Norman Tebbit, with whom, it is said, she had had some acrimonious rows, even though they were politically of the same kidney. But fences were mended - temporarily at any rate.
This campaign, however, was on the face of it a disaster. There was bickering within Central Office as Mr Tebbit accused Lord Young of interfering with his proposals. And towards the end, Mrs Thatcher, on so-called "wobbly Thursday", went into a rage as at least one opinion poll showed Labour hot on her heels.
It gave her and her colleagues a chilling fright. The Tories were almost certainly helped by Labour's over-slick and, if anything, too professional campaign, and by the Opposition's inability to produce an acceptable defence policy.
Mrs Thatcher made several blunders herself during the campaign but perhaps her strongest card was to proclaim that the possession of nuclear weapons had brought about 40 years of peace. And that the ostentatious strength of the West had led the Soviet Union to meet them on disarmament proposals.
The Prime Minister wanted not just to win that election, but to win by a large majority so that she could still retain foreign confidence in her. As it was she swept home by a 101 majority this time, a much relieved woman.
Once again, she could at least partially thank Labour for her victory since their campaign was even worse than the Tories'.
Immediately after that election victory, she set about an inner-city clean-up policy designed to sweep Labour out of office in key city councils. But things were starting to go wrong again. Inflation began to creep up, and her policies towards the National Health Service were being greeted nationwide with suspicion and dislike.
Mrs Thatcher's final 12 months in Downing Street were uncomfortable, full of rumblings, dangerous discontent among some of her Cabinet ministers, whispering on the backbenches, calamitous by-election defeats, and a feeling nationwide that the "indestructible" lady had been there too long, and was fraying at the edges.
She remained totally dominant, but there were moments when her boldness began to look more like rashness. It started in July 1989 when she unceremoniously ejected Sir Geoffrey Howe from the Foreign Office, invested him with the spurious title of Deputy Prime Minister, and made him Leader of the Commons.
John Major, who was then no more than a face in the crowd, was put into the Foreign Office.
Her removal of Sir Geoffrey was in fact an appalling misjudgment that she was to live to regret. She could never believe that the mild-mannered, avuncular shambling figure was to be the one whose savagery, 16 months later, catapulted her from power.
Then, three months later Nigel Lawson - described by Mrs Thatcher only days earlier as "unassailable" - resigned as Chancellor of the Exchequer. Lawson believed that the regular presence in Downing Street of her adviser, and "family friend", Sir Alan Walters, a bitter opponent of European union, and an unrepentant monetarist, undermined his position as Chancellor. He could no longer continue.
It was a shattering blow to her Government. But she responded immediately, by putting Mr Major in the Treasury where, a few months earlier he had been Chief Secretary.
This provoked a slow but perceptible and uncontrollable movement of earth which gradually gathered the momentum of an avalanche and which finally tossed her out of office a year later.
Sir Anthony Meyer, an old and obscure but embittered Tory backbencher from North Wales, dared to challenge her for the leadership. She won by 314 votes to 33, but it was an omen. The result meant that some 60 Tory MPs had either voted against her or refused to vote for her. It was very bad news indeed.
And as the months slid nervously by, two more veteran Cabinet ministers deserted the ranks, Sir Norman Fowler (Employment) and Peter Walker (Wales). Although both ostensibly left for personal reasons, it began to appear that her government was crumbling fast.
Then came the disastrous by-election defeat in Tory-rock-solid Mid-Staffordshire in March, 1990, caused by the suicide of the sitting MP John Heddle. Labour, astonishingly, swept the Tories out. It looked like the start of something bad. And it was.
There was even worse to follow. The subsequent defeat in the Eastbourne by-election was particularly poignant for Mrs Thatcher since the vacancy was caused by the IRA assassination of her dear friend Ian Gow, a tireless pro-Unionist crusader for peace in Northern Ireland.
This was followed by the Bradford North by-election where the Tories, in this once-Conservative seat, were driven into third place. The opinion polls were bad. There was debris everywhere.
It was, however, the European Summit in Rome in early November which set up a train of events which propelled Mrs Thatcher out of Downing Street.
She returned to Britain fulminating about the way the summit was conducted, accusing the hosts of incompetence. This was more than Sir Geoffrey could stomach.
A few days later, he knocked on Mrs Thatcher's study door at Downing Street, and presented her with his resignation. She was shocked. But the consequences were even more catastrophic.
Michael Heseltine, who had stormed from the Cabinet five years earlier over the Westland affair, wrote an open letter to his Henley constituency party overtly attacking the Prime Minister's handling of European affairs.
Then he slipped off to the Middle East amid a raging storm, still protesting that he would not, nevertheless, challenge Mrs Thatcher in office.
Sir Geoffrey returned centre-stage. He made a resignation statement in the Commons so untypically ferocious and damning that Mrs Thatcher, bleak-faced, could scarcely believe what she heard. She visibly wilted as Sir Geoffrey plunged in the dagger and twisted it without mercy. The words were so shocking that MPs audibly gasped at their savagery.
If she had not realised it already, Thatcher must then have known that her time was nearly up.
The awful power of that statement almost physically compelled Mr Heseltine, the following day, to challenge her for the leadership. She went to a summit in Paris and, to her dismay, just failed to get enough votes to score an outright win on the first ballot.
With "defeat" written all over her face, she said she would fight on "to win". But minister after minister warned her that by fighting on she stood the prospect of humiliation in the second ballot at the hands of the man she despised more than anyone else in the Commons.
So, the following morning, she stunned the world by announcing her resignation. Her exit was as grand as were all her entrances. She followed this up by delivering a shattering speech in the Commons in the face of a vote of no confidence.
At one point in it, she stopped momentarily and declared, almost with surprise in her voice: "I'm enjoying this." It was as though the shackles had been magically removed from her after 11 years.
Her downfall was a mixture of skulduggery among some of her colleagues, and a fear among others that people were getting bored with her to the extent that they would vote anti-Tory at the next election just to see a fresh face in power.
There were tears visible in her eyes as she was driven away from Downing Street for the last time after 11 years as Prime Minister to hand in her seals of office to the Queen.
Some days later, the Queen appointed her a member of the Order of Merit and her husband, Denis, was made an hereditary baronet. She was "deeply honoured" for her own part and "thrilled and delighted" for Denis.
But she insisted then that she wished to remain plain Mrs Thatcher.
It was not long, however, before she entered the House of Lords. She seemed incapable of living without some confrontational forum in which to operate.
And there was no diminution to her style. It was as fiery, unequivocal and straightforward as ever. Her ardour was undimmed and her contributions were no less full-blooded than ever they had been.
She was an extraordinary woman, who never understood why the Tories had discarded her. And she found life virtually impossible to live without a battle to fight - and to win.
Mrs Thatcher summed up, with remarkable prevision, her own beliefs three years before she became Prime Minister and just after the Kremlin had dubbed her - flatteringly, she thought - the Iron Lady.
She told her audience: "I stand before you tonight in my green chiffon evening gown, my face softly made up, my fair hair gently waved . . . the Iron Lady of the Western World? Me? A cold war warrior? Well, yes - if that is how they wish to interpret my defence of values and freedoms fundamental to our way of life."
Although Margaret Thatcher normally enjoyed robust health, she suffered one or two setbacks along the way. She was taken ill briefly once in Sri Lanka, damaged her ankle during a fall at a Conservative Party conference in Bournemouth, and suffered a minor stroke while on holiday with Sir Denis in Madeira late in 2001.
But she bounced back from all these setbacks. And in March 2002, she published her latest book, Statecraft.
It was around this time that her doctors told her that she must make no more public speeches, an instruction which she did not obey to the letter.
Then she suffered a devastating blow in June, 2003 when her husband, Denis, died after a short illness. He had seemed to have recovered from a six-hour heart bypass operation he had undergone some months earlier.
At the subsequent funeral service, Lady Thatcher looked frail and woebegone. At that time, stories started to emerge that she was losing her short-term memory and easily becoming confused. But she continued to attend the House of Lords from time to time.
It looked as though it was going to be a sad end to the life of such a powerful, decisive, fearless and honourable woman. However, her health appeared to improve after a visit to South Africa, and she started to make more regular appearances in the House of Lords.
Meanwhile, the 25th anniversary, in May 2004, of her accession to Downing Street as Britain's first woman Prime Minister, was celebrated with a lavish dinner at London's Savoy Hotel at which, defying doctors' orders, she spoke robustly, attacking the Blair Government and praising Michael Howard, the new Tory leader.
A year later there was to be another such occasion, this time at the Dorchester, to mark the 30th anniversary of her election as Tory leader in 1975.
But amid all these celebrations, there was a new and unpleasant shock for Lady Thatcher on the horizon: the arrest in South Africa on August 25, 2004, of her devoted son Sir Mark Thatcher, who was charged later with contravening two sections of South Africa's Foreign Military Assistance Act which bans residents in that country from taking part in any foreign military activity.
The charges related to "possible funding and logistical assistance in relation to an attempted coup in Equatorial Guinea" organised by Thatcher's friend Simon Mann.
By now Lady Thatcher, who doted on her son, was not in good health and there were genuine fears that her condition might worsen as a result of this affair.
There was every possibility that Mark might face a long jail sentence or worse, if he was extradited to Equatorial Guinea. It was a real fear.
He was released on two-million rand bail and spent some time under house arrest. He was later bailed to London to live with his mother.
Ultimately, to huge relief all round, following a process of plea bargaining, he pleaded guilty to the less serious charge of investing in an aircraft (used in the unsuccessful coup attempt) without making proper investigations into what it would be used for.
He was fined three million rand (about £245,500) and received a four-year suspended jail sentence.
In June 2004, Lady Thatcher attended the funeral service in Washington of her "dear friend" Ronald Reagan. In a moving, pre-recorded tribute, she said: "We have lost a great president, a great American and a great man. And I have lost a dear friend."
And in February, 2007, Lady Thatcher became the first ex-Prime Minister in history to have a statue of herself unveiled in the House of Commons while she was still alive.
At the ceremony, the Iron Lady said: "I might have preferred iron, but bronze will do. It won't rust and this time, I hope, the head will stay on."
This was a reference to the fact that some years earlier a political activist had decapitated a marble statue of her on loan to London's Guildhall.
Then, shortly after Gordon Brown - who had earlier praised Lady Thatcher as a "conviction politician" - became Prime Minister in June, 2007, he invited her into Downing Street, an event which created anger in some sections of the Labour Party.
But this was exactly what Tony Blair had done ten years earlier, soon after he entered Number 10.
There was another health scare in March, 2008. Lady Thatcher had succumbed to the heat at a dinner in the House of Lords, and fainted. She was taken to nearby St Thomas's Hospital for tests, but allowed to go home the following day.
And then in the late spring of 2009, she fell and broke an arm. She underwent an operation to have her arm pinned.