SHE is as divisive in death as she was in life – or so everyone has been saying about the passing of Lady Thatcher.

In fact, you could equally argue the reverse. The left hasn't been more united for years – and nor has the right – in its hatred for the street parties and singalongs that have followed in her wake. At times last week I felt as if I had been transported back to the 1980s, watching crowds chanting "Maggie, Maggie, Maggie" in Glasgow, Liverpool and Brixton.

The day after her death was announced, Boris Johnson delivered a politically charged eulogy in the Daily Telegraph. "You either gave in to the hunger strikers, or you showed a grim and ultimately brutal resolve," he roared, referring to the IRA hunger strikers of 1981. "You either accepted an Argentine victory or else you defeated Galtieri. You either took on the miners or else you surrendered to Marxist agitators."

That exercise in tasteless triumphalism was bound to provoke a response even from those who do not glory in confrontation. Thatcher, remember, also gave comfort to dictators like General Pinochet, promoted homophobia with Clause 28, opposed the liberation of Nelson Mandela, closed down the mines, introduced the poll tax, destroyed manufacturing industry and demonised modern Germany and the European Union.

The Mayor of London has been calling for a statue to be erected in Mrs Thatcher's memory, perhaps even on the fourth plinth of Trafalgar Square, which would be madness. It would rapidly become the most vandalised and desecrated memorial in Britain.

And then there is the extraordinary decision to give Thatcher what is effectively a state funeral, with gun carriages, the Queen and Jeremy Clarkson in attendance. It is one thing to give a state funeral to a genuine national leader, like Winston Churchill, who led a coalition government during the Second World War; it is quite another to give a similar send-off to a politician who simply divided the country along class and north-south lines.

Street parties and renditions of Ding Dong! The Witch Is Dead have been denounced as tasteless. And perhaps it is a bit silly to indulge in this nostalgic class warfare, since this is not the 1980s, even if it feels that way. However, the reaction on both sides has demonstrated that the wounds that were opened during that decade have not been healed by the passage of time.

My own professional history was dominated by Margaret Thatcher, a politician I only met four times and interviewed twice but who hung like a shadow over Scottish political life. On the day she was elected in May 1979, I felt, like many in Scotland, an ominous sense that things would never be the same again.

Fresh out of university, I'd had the dubious fortune to start my journalistic career in the BBC's Referendum Unit, at the time of the abortive devolution vote of March 1979. Scotland had voted "Yes" but was denied the Scottish Assembly because of the infamous 40% rule, which said 40% of the entire electorate had to vote yes.

That led directly to the dawn of Thatcherism because the SNP MPs in Westminster, in their fury at the loss of an assembly they didn't really want, withdrew support for the Callaghan government in the crucial confidence motion later that month. It was an act of unpardonable folly by the 11 SNP MPs, even though David Steel's Liberals were also implicated.

In the May election, which brought Mrs Thatcher to Number 10, the SNP lost all but two of their MPs, and were plunged into political obscurity for the next decade. Even worse, their stupidity helped leave Scotland politically undefended in a crucial decade. The incoming Tories concluded that Scotland wasn't a problem any more, with devolution defeated and the SNP back in their box, and that consequently our industrial economy could be sacrificed in the class war. It's an outcome that Scots might do well to reflect upon in the run-up to the 2014 referendum.

Anyone who thinks Thatcherism was a good thing for the Scottish economy, clearly wasn't around at the time. In the early 1980s I was working as a presenter for the BBC Scotland documentary series Current Account, which charted the social and industrial consequences of the Thatcher recessions. The Singer factory in Clydebank, Invergordon's aluminium smelter plant and the last car factory in Scotland, Linwood ... by the end of 1981, they had all closed. We filmed factory occupations at Plessey Electronics and British Leyland, Bathgate.

We watched as Scotland's steel industry was run down and the shipyards dismantled. And it was blindingly obvious to everyone except Arthur Scargill that Thatcher was storing up coal stocks and political capital so she could take on the miners in 1984. I spent a large part of the strike seeing the life drain out of pit towns like Polmaise as the tragedy unfolded.

For nearly a century, Scotland had been a world leader in engineering technology, with Glasgow and Clydeside the industrial heart of the British empire. That was swept away in less than a decade. Around 400,000 jobs, mostly in west-central Scotland, were destroyed during the Thatcher recessions, and although many were replaced in electronics assembly plants, Scotland's industrial economy was not.

It was an irony entirely lost on the Scottish Tories that the electronics firms that came to "silicon glen" in the 1990s were attracted by the very state subsidies Thatcher had withdrawn from Scotland's indigenous manufacturing industry, and because of Britain's membership of an EEC she abhorred. Most of them left within 15 years, leaving the de-skilled and demoralised Scotland we see today. Research has demonstrated that Scotland's notorious health problems date directly from this period, which was the economic equivalent of warfare.

Modernisation it wasn't. During the same period, the Germans did not destroy their industrial base in Bavaria, they re-tooled it. In Scotland, opportunities to rebuild on the basis of the oil industry were missed. And what made this profoundly unsettling was the knowledge that the destruction of manufacturing industry was being financed by Scottish oil revenue which, during the 1980s, was pouring into the UK Treasury, masking Britain's balance-of-payments deficit. Estimates of the value of North Sea Oil during the Thatcher era vary from £100 billion to £200bn. But what is not in doubt is that it was oil that kept the UK in business in the 1980s.

Of course, Scotland received its share: in the form of unemployment and invalidity benefit. This kind of scorched-earth policy would not have been possible in the southeast of England because it would have been politically unthinkable.

Historians tut-tut if you suggest that there was a Scotland-England dimension to Thatcherism because that smacks of nationalism. But it was glaringly obvious at the time, even to non-nationalists like me. Her policies, designed to destroy trades unionism by laying waste to manufacturing industry, were in the direct interests of the City of London financial classes.

The other side of the collapse of Scottish industry was the "big bang" of 1986, which deregulated British banking and gave birth to the reckless financial-services "industry" we see today. Thatcher's privatisation of utilities such as gas, electricity and British Telecom earned huge commissions for City of London firms that handled the flotations and speculated on the share prices of state assets. The Russian oligarchs imported her business model to their own country. Scottish & Southern Energy, recently charged a record £10.5 million by Ofgem for mis-selling, is part of the Thatcher legacy.

Thatcher's policy of council-house sales further benefited the banks and finance houses, which sold the mortgages and raked in the profits, mis-selling dodgy endowment mortgages in the process. Britain turned into a nation of estate agents, and the value of homes in the southeast and in London rocketed, benefiting the middle-class Tory voters who made capital gains through property speculation. The Lawson tax cuts, which reduced the top rate of income tax from 83% to 40% in 1987, further enriched the wealthy middle classes of the southeast of England by allowing them to keep most of it. Meanwhile, Scotland got the poll tax.

In 1987, I'd just become the BBC's Scottish political correspondent, and was furious that Margaret Thatcher refused to give us an interview in the run-up to the General Election. I shamelessly hijacked a packed press conference at the start of the campaign and threw questions at her from the floor. It was insulting to the other journalists present but, sensing the moment, they remained silent when she tried to move on, and we got our interview.

Being in Mrs Thatcher's bad books wasn't a very sensible career move, but the poll tax was a unique moment in Scottish history. Questions had to be asked about how this policy could be imposed on a country which had firmly rejected it at the ballot box. Scotland wasn't used as a "guinea pig" as Tory apologists always point out. But the poll tax was introduced a year ahead of England and in the teeth of widespread opposition across all classes. That opposition had been expressed at peaceful demonstrations and in the 1987 election, where the Tories were routed in Scotland.

But what was worse was that the poll tax was only scrapped in 1990 following riots in London. This delivered a sobering message to Scots that peaceful expressions of dissent are not heard in Westminster, and led to the massive endorsement of devolution in the referendum of 1997. It also caused the wipeout of Tory MPs in the general election of the same year. It wasn't the industrial closures as such, but the manifest unfairness of a tax which expected a duke to pay the same as a dustman, that forced Scotland to rethink its place in the United Kingdom. It also sealed Margaret Thatcher's fate.

I was back in London working in Westminster in 1990 when she resigned after Michael Heseltine finally stood against her. Distraught Tory ministers such as Michael Portillo and Michael Forsyth, some in tears, gathered in the Members' Lobby at Westminster, promising revenge against the Cabinet "wets" who had brought down their leader.

But there was also a great deal of relief among Tory MPs who feared for their seats, and were genuinely worried about what she was doing to the country. Thatcher was never a true Conservative, after all. Her ideological populism, class confrontation and military sabre-rattling were not at all in the Tory tradition, which is why so many of her Cabinet ministers trooped in to Number 10 in November 1990 to tell her the game was up.

By then, however, the damage had been caused. Britain would never be the same again. Scotland set up its own parliament and opted out of UK domestic politics. The City of London – a Frankenstein's monster largely of her creation – went on to bring down the entire financial system.

Commentators say it is wrong to blame politicians for the bankers' greed, but they were the direct beneficiaries of her industrial policies and also of the amoral climate of possessive individualism which she introduced to Britain – a travesty of the economic philosophy of Adam Smith, whom she claimed as a mentor.

And today her policies are being pursued again by David Cameron, despite the image of "liberal" Conservatism. We have the bedroom tax in place of the hated poll tax. And yes, I know it isn't a tax, but nor was the poll tax. It was officially called the "community charge" and the BBC got into exactly the same difficulty for not naming it as such. Margaret Thatcher cut pensions by not raising them in line with average earnings after 1981. Tories today are cutting all benefits by raising them by less than the rate of inflation. Thatcher was profoundly hostile to Europe, but it has taken David Cameron to offer Britain a ballot on withdrawal from the EU. She may be gone, but her work remains.

Why did Scots find her so abominable? After all, Scotland used to be a Tory nation in the 1950s.

The answer lies in a potent mix of anti-Englishness, moral indignation, legitimate grievance and philosophical revulsion. Her Sermon on the Mound in 1988, with its crass celebration of wealth, offended something deep in Scotland's Presbyterian soul. It convinced Scots that they really did live in a different country, and began the process that could still lead to Scotland leaving he UK for good.

The cross-party Scottish Constitutional Convention was set up in the same year as the poll tax and within a decade Scotland had won a parliament with primary legislative powers. Now, Scotland faces a referendum on independence.

If they do erect a statue, it should really be outside the Scottish Parliament in Holyrood. After all, Margaret Thatcher was the politician who made Scottish home rule inevitable. And she may yet cause the break-up of Britain.