As a boy, growing up in Hampshire, Geordie Greig was aware of the filing cabinet of family letters in his parents' home that had belonged to his famous grandfather. Sometimes, out of ordinary curiosity, he would idly riffle through the cabinet's contents and look at the letters and ponder about the life his grandfather must have led.

By any account, it was an extraordinary collection of letters from a remarkable number of some of the most important and influential men and women of the century. It also indicated someone with a highly eclectic set of correspondents: on the one hand, George V and Queen Mary, Dwight Eisenhower, Ramsay MacDonald; on another, Johnny Weissmuller, the actor who first brought Tarzan to life on the Hollywood screen, Jimmy Durante, Bud Flanagan and John Wain.

Louis Greig, the boy from Glasgow who became the friend of three kings, the son of a Scottish merchant who had sat with the little Princess Elizabeth on his knee at Wimbledon, had travelled a very long way from Kelvinside and he seemed to have known just about everybody. But there was one man he knew better than most: Prince Albert, the Duke of York, the man known as Bertie to his family and as George VI

to the rest of us. Louis Greig should be remembered for many things, but undoubtedly his most significant role was, as he was later to be described, that of ''the man who made the King''.

He was friend, mentor and guide to the future George VI. He was one of the most influential men in royal circles for years, and the most important courtier to George VI during the years the prince was growing up. It is arguable that he also saved the young man's life. In view of this alone, it is really very surprising that some sort of version of this book has not been attempted before; but it was just as well that nobody had previously tried to do so, for really nothing could match comparison with the archive of family material on which Geordie Greig has been able to draw.

Yet even without the story of his almost unparalleled influence on Prince Albert and the part he played in the life of the British royal family over a significant period of its history, Louis Greig's own life was one of achievement in a whole range of other spheres. He was captain of the Scottish rugby team. He played tennis at Wimbledon, partnering Albert, then the Duke of York,

in 1926.

He was a distinguished surgeon who was decorated for his medical advice. He was, variously, an officer in the Royal Navy,

a Royal Marine and an

RAF pilot.

He was wounded and taken prisoner by the Germans in the First World War and he was personal air secretary to Winston Churchill in the Whitehall war bunker in the Second World War. He was a fixer, a man of quite astonishing influence behind the scenes of the British establishment, conveying the political wishes of prime ministers and presidents to editors

and equerries.

An even greater measure of the man is provided by the fact, as his grandson records, that at his funeral in 1953 there were represented not only the five most senior members of the royal family, but also Winston Churchill, J Arthur Rank, Catford dog track, the All-England Wimbledon tennis club and the Scottish rugby team. There were six waiters from the Dorchester Hotel, who had taken the morning off

to attend, also present in

the church.

Geordie Greig was aware of this, of course, as he grew up. He is a journalist, nearly 40 now although he looks years younger, fresh-faced and in some ways almost unbelievably boyish for someone who has lately been appointed as editor of Tatler - the oldest magazine in Britain dealing with society matters, as he carefully describes it. Although he is far too well-mannered to draw specific attention to the fact, he is himself naturally something of a toff, and as toffs do, he went to Eton.

''When I was at school,'' he recalls when we meet, ''people who were quite elderly would sometimes say: 'You're not related to Louis Greig, are you?' And then they would murmur something about 'played tennis with the king'. It was an epsiode that was much recalled by that generation, although the famous partnership was humiliatingly defeated. It was the high point of their friendship but the low point of tennis,'' says Geordie Greig. This man, whose father was a godson of Queen Mary and whose aunt was the goddaughter of George V1, started work in journalism as a crime reporter in Deptford on the South East London and Kentish Mercury. It was, he offers dramatically, where Marlowe was murdered a few centuries before and, if anything, crime had possibly got a little worse in the area by the time he, young Geordie, got there. His contacts included a meaningful working relationship with Charlie

Richardson, of gang fame.

Oddly enough, all this might possibly be quite a useful training ground for a man who has now reached the dizzy and demanding heights of editing Tatler; what with ''society'' not being exactly what it used to be. We will return to this point. In the intervening years, young Greig has also worked for the Daily Mail, briefly, during its very brief life, for Sunday Today (where the Prime Minister's press secretary, Alastair Campbell, who now ranks as one of the most powerful people in Britain, was his news editor) and for the Sunday Times, for which he was New York correspondent and literary editor. It was during his spell on Today that he interviewed the biographer Michael Thornton who opined, in passing, that there were two unwritten books about the royal family that deserved attention: one a portrait of the present Queen's marriage and the other 'the man who made the King, a chap called Louis

Greig'. ''That's my grandfather,'' said the young reporter.

His interest was sharpened, but it took the intervention of Geordie's wife, Kathryn, three years ago at a literary festival before the book took shape. She mentioned the existence of the family archive to the literary agent, Ed Victor, and the book was born. It is a truly fascinating account of political power and influence, of the state of the court in the inter-war years and of the life of one highly unusual son of Glasgow. Geordie Greig writes: ''Glasgow provided the essential ingredients for the making of Louis.''

Louis Greig was the ninth of the 11 children born to David and Jessie Greig, nee Thomson, in the latter years of the last century. He arrived in November 1880 in the long line of poor Jessie's endless pregnancies; she gave birth on average every 18 months for 24 years. Louis was born in the family home at No 18 Lynedoch Crescent in the west of Glasgow. It was a comfortable home; his father was a successful commodity dealer, trading as Greig, Leisler and Co, and he gave his fifth son, Louis, the middle name of Leisler as a mark of respect to his German business partner. Louis dropped it in 1917 at the same time as George V reluctantly removed references to his own German antecedents. He was a sporty, lively little boy who went first to Glasgow Academy and then to Merchiston Castle School in Edinburgh. He was clever, smart, an outstanding athlete and - perhaps not surprisingly for someone from

such a large family - very competitive.

And he wanted to join the Royal Navy. He had missed his chance of becoming a cadet, having been too busy with sport at school which led him to the distinction of becoming captain of Glasgow Academicals. The only route to sea which was left to him now was through medicine; it was also to steer him a little later towards Prince Albert. Louis went to Glasgow University in 1898 and his later experience as a young doctor in the city would mark him for the rest of his life,

notwithstanding the social heights he was

to scale.

He walked through the Gorbals, his doctor's bag providing him with

free passage, and he was horrified. ''He has this wonderful family life at home and then he goes out and works in the Gorbals and he is absolutely appalled by what he sees,'' says his grandson, using the present tense as he relives the experience. ''He is desperately moved by the conditions of people in the slums and the sense of injustice never left him.''

It was this, Geordie thinks, which explains why his grandfather - despite his position in society, his place in Palace politics and his role under Churchill during the Second World War - voted for the Labour Government which took office at the end of the war in 1945. That was a crucial political election and it is a fascinating insight into Louis Greig's judgment of events that he did take that step. His grandson also thinks that the same political sentiment - in the finest sense - underlay the friendship Louis had formed with Labour's first Prime Minister, Ramsay MacDonald, and with the biscuit manufacturer and philanthropist Alexander Grant. The three Scottish friends came to be known as Money, Power and Influence; Grant was Money and Ramsay Mac was Power. There was never any doubt who Influence was.

Louis and Albert first met on the Isle of Wight. The prince was a naval cadet at Osborne, 13 years old, hesitant, stammering, unsure of himself and ill with whooping cough. Louis was a surgeon-lieutenant in the Navy, who had already attracted the attention of George V on the rugby field. He was famed for his swearing: it was said that people didn't go to see Greig play, they went to hear him. He had once dropped a ball directly in front of the King, who was seated in the royal box, and being aware precisely of his position on the field, Greig had apparently said: ''Oh b . . . other'', and met the King's amused glance in return.

Louis was called in to treat young Albert when he suffered a bout of flu and whooping cough and the royal family was extremely grateful for his assistance.

The boy got better, of course, but more than that, his parents liked the approach of Louis, this no-nonsense Scot who could not be more dissimilar from the normal run of court sycophants. George V described him as The Tonic. ''The King and Tonic'', the pair of friends were later to be nicknamed.

Geordie Greig quotes one contemporary view: ''The Czar chose Rasputin; George V chose Louis Greig.'' And here there is suddenly an echo today. The rest of

us may perhaps forget - or never need to realise - that it is necessary for those

who may one day take

the throne to be appropriately groomed for this role. Only recently

there has been discussion in the newspapers about a young man, Edward van Cutsem, who is reported to be performing this task for our current heir to the throne, Prince William.

The job that van Cutsem is conducting sounds in some ways really very similar to that performed by Greig, who was 30 when he first met the 15-year-old Albert, Duke of York. Interestingly, like Greig's relationship with Prince Albert, van Cutsem, at 26, is significantly older. The difference is that Prince Albert was a younger son and all that was going on in his education and introduction to society was being conducted against the backcloth of an elder brother, the future Edward VIII, who it is assumed will become king. There are not many who are looking at Albert's education with a view to his possible succession to the throne, but there are some. One was Clive Wigram, one of the secretaries to the King who suggested, with astonishing percipience, in 1923 that Edward would never be King.

After their first meeting, Louis and the prince were to be bound together by the shackles of contemporary history. The King saw to it that the two men served on the same ships together and Louis was given responsibility as a mentor to the diffident young prince. They were together until Louis's capture by the Germans in the First World War and, upon his release, he was summoned to Buckingham Palace on the very day he got out. The court circular reveals that the King saw two people that day: Kitchener and Louis Greig.

In the meantime, the Prince was endlessly ill with an undiagnosed ailment. He felt additionally wretched because all his friends were serving, dying or being imprisoned. Greig was asked by Albert's parents what he would do if it was his son who was ill and he recommended an investigative operation. It was carried out and showed that the prince had a duodenal ulcer. He got better; Louis got

an MVO. Queen Mary called Greig the man who saved her son's life, and from then on the relationship between him and the royal family is continually strengthened. When Albert and his brother Henry, the Duke of Gloucester, go to study at Cambridge, it is Greig who rents a house at the King's expense and lives with them. When Prince Albert leaves the Navy for the Royal Air Force, Louis does, too, and learns to fly at the age of 40. They play tennis together: Louis teaches him; the famous Wimbledon incident ensues. Louis plays a significant part in the wooing and eventual marriage of the Prince with Elizabeth Bowes-Lyon, now the Queen Mother.

And when eventually a distance arrives in the relationship, it does not in any way diminish Greig's extraordinary position in society: he just moves on and moves his influence in different ways. He is knighted by Ramsay MacDonald for political services. He is close to the Palace and to Prime Ministers and to Fleet Street. He is eyes and ears and contacts. He defines networking before it's even been invented, and possibly even spinning too.

He was a man of extraordinary resourcefulness. He was chairman of Wimbledon for years and it was he who had the idea of bringing in the ballboys from Barnados. When there was a small crisis because the lady tennis players wanted - and needed - professional massage, but in those delicate days earlier in the century they could not contemplate being seen by the then exclusively male masseuses, Greig had the brilliant idea of finding a blind masseuse to treat the

women players.

His grandson believes there is a curious similarity that might usefully be explored about the extent of the influence of a small Scottish political mafia then - Greig, MacDonald, Grant - compared with all the Scots in positions of power in the British establishment today. The sort of people who make things happen. It didn't matter, explains his grandson, who has been investigating all of this, whether it was a question of getting a lawnmower or the Prime Minister's ear, Louis Greig was the man.

He made things happen. He was immensely good at it and popular, besides. Everyone liked him.

And now? Well, perhaps in a way it is not so strange, a couple of generations down the line, that his grandson has become the editor of the oldest magazine in Britain dealing with society matters. ''Society today is extremely interesting,'' declares young Greig and, yes, he's right. And his own career equips him for dealing with it: as well as his fashionable years in journalism, he spent his gap year before university wearing a dhoti and teaching in a village in South India where he was the only white person for 500 miles. Not a bad preparation for editing Tatler today, one imagines.

He recognises how society has changed; for heaven's sake, even after only a few weeks as editor of Tatler, he ought to know. What passes for society today takes in the whole panoply, he says, from duchesses to entrepreneurs (and perhaps one or two who are both?); from Salman Rushdie to the Sultan of Brunei, from It Girls to today's biscuit manufacturers. Under his editorship, he announces, the magazine will be elitist, rather than snobbish; it will be wide-ranging and full of surprises; funny but sometimes serious, and sometimes sensational. That is a definition of what all editors seek. However, few of them - other editors running a society magazine - can have had quite the claim on society history that equals the line that leads to Geordie Greig. Only time will tell the extent to which it proves a real advantage.

l Louis and the Prince: A Story of Politics, Intrigue and Royal Friendship, by Geordie Greig, is published by Hodder and Stoughton at #20.