Born into a theatrical family, novelist Compton Mackenzie

grew up to

mix with the aristocracy.

A snob and

a social climber, some claimed. Not a bit of it, say those

who remember him from his days on Barra

A summer evening at Connel, Argyll. My grandmother takes my hand down the lawn, round to the ruins of Dunstaffnage House. In December 1940 a log rolled from a dressing-room fireplace and set the mansion ablaze. The burn running through the wood was frozen, so the hoses couldn't operate. We stand at the front, looking at great windows open to the sky. Eight years on, the rubble is still being searched for one of the treasures of Scotland, the gold medal of the Darien Venture, presented to Campbell of Fonab.

Angus Campbell appears, out for an after-dinner stroll. The twentieth Hereditary Captain of Dunstaffnage and Keeper of the Royal Forest of Dalness is wearing a tartan evening suit with braided sleeves. Dunstaffnage was refused a commission in the Guards in 1914 for health reasons. He appears next in 1917, puttering over the steppes on a motor cycle, and crashing into a dead horse. He has come to offer his services to the White Russians in their fight against the Bolsheviks. Dunstaffnage was a Russian scholar. At the age of five my brother Angus would get a piece of chocolate cake for pronouncing correctly the names of the Russian generals who had defeated the Nazis.

This evening Dunstaffnage is wearing round his neck the gold key as Marnichty (keeper) of Dunstaffnage Castle for the Duke of Argyll. He comes and stands beside us at the bay window, where the drawing room had been, and picks up a shard of melted glass. ''My guests used to sign their names with a diamond on the panes,'' he explains. ''Just before the war I had a Polish Count staying. He left a hamper of wine, saying he was going to come back and drink it with us, but I fear he ended up in a concentration camp. And Compton Mackenzie also signed his name.''

The millions of viewers who are following avidly the modernised television adaptation of Mackenzie's The Monarch of the Glen, set in a Highland castle, may well wonder if the author was a snob. Certainly any man who plans and publishes ''octaves'' of his autobiography, dividing his long life into eight-year spans, and peppers them with the names of the titled, must have enjoyed such company. In Octave Eight, covering the years 1931-38, there are photographs of Angus Campbell of Dunstaffnage with Lady Elspeth Campbell, the Duke of Argyll's sister; and the Lovat Frasers at Beaufort Castle on Jubilee Day. But to see Mackenzie as a social climber is to misunderstand the nature of the man.

Compton Mackenzie was born into a theatrical family. His father, Edward Compton, had formed his own touring company, the Compton Comedy Company (CCC). Andro Linklater records in his excellent biography of Compton Mackenzie: ''A policy of giving the public what they wanted - in Cork, for instance, he [Edward Compton] allowed the plays to be selected by public vote - combined with rigorous economy, made the CCC a financial success from the start.''

Edward married his leading lady, Virginia Bateman. When the CCC reached West Hartlepool in January 1883 the labour pains began. It was a forceps delivery. A month later the boy was christened with the names of his father, paternal grandmother and the family stage name, and in the parish register his surname was entered as Mackenzie. Edward Montague Compton Mackenzie was too much of a mouthful, even for an actor, so it was reduced to Monty.

It was the kind of itinerant background that the aristocracy would have looked down on. You were entertained by actors; you didn't entertain them.

But Mackenzie was brought up in comfortable circumstances, with two servants, a cook and a housemaid - more than many an impoverished aristocrat could boast. And you could rely on thespian parents to give you a beautiful speaking voice.

Mackenzie was educated at St Paul's school, then went up to Oxford. Instead of sporting prints, Monty preferred editions of Rabelais and Verlaine on the walls of his rooms. Andro Linklater records: ''Outside the college he became a member of the Strafford Club, a bastion of High Toryism, the Grid, a dining club for social bon viveurs, and the Oxford University Dramatic Society. In each of these circles, he became the epitome of its type, and took the part with a panache that swept everything before it.''

But Monty wanted to be a writer, not a social lounger. At the beginning of his third year at Oxford he moved out of college into rooms shared with his closest friend, Harry Pirie-Gordon, only son of an Aberdeenshire laird.

Here was a comic model for the fiction to come. Pirie-Gordon was friendly with Harold Davidson, the rector of Stiffkey, who was to be unfrocked for importuning young women, and who would be killed by a lion at Blackpool. Another friend was the would-be priest Frederick Rolfe, or Baron Corvo. Mackenzie made his reputation with Sinister Street (1913/14). The American novelist Scott Fitzgerald was ''drunk with Mackenzie''; the more sober Henry James hailed him as the ''greatest talent of the new generation''.

When does Mackenzie's infatuation with Scotland begin? In 1925 the three Shiant Islands in the Minch were knocked down to him for a bargain #500. Octave Eight has a picture of the handsome Scottish Nationalist Compton Mackenzie when he was elected Lord Rector of Glasgow University in 1931. He wrote proudly to his mother: ''I am the first Catholic Rector to be elected since the Reformation, and the first literary man since Macaulay, but he was a politician as well. Even Sir Walter Scott was defeated twice.''

Mackenzie was hyperactive; novelist, joint founder of the Gramophone magazine, proprietor of islands, politician. London should have been his stamping ground, consorting with the literati and the aristocracy, so why go to Barra?

''I met the Coddy first at the Inverness Mod in 1928 and made up my mind immediately that I must lose no time in visiting Barra in order to enjoy more of as good company as I have ever known,'' Mackenzie recorded.

John Macpherson, the Coddy, mine host of a boarding house on Barra, was one of the great tradition-bearers of the island. Such was Mackenzie's attachment to Barra that he decided to build himself a home there, by the cockle strand. The 14-roomed bungalow became the centre of the social life on the island - at least for males.

I cherish the letters I receive from Margaret Fay Shaw Campbell. She wrote last October in the midst of an ''equinoctial upheaval'' on Canna: ''this

70-year-old Imperial typewriter was given to me by Compton Mackenzie in 1962 when I had a detached retina. It has been my beloved companion from that day forth.''

Mackenzie records in Octave Eight: ''While we were in South America John Lorne Campbell had been sensible enough to fall in love with Margaret Fay Shaw, and this June (1935) he and she were married in Glasgow, the service being conducted in Gaelic. Margaret was a Pennsylvanian who as a girl in her teens had bicycled all over the Outer Isles with two other young American girls.

''She had been captivated by this tiny world by which I had been equally captivated, and had been spending more and more of her time there. She was completely at home in South Uist, her favourite island, and the people took her to their hearts. She was an artist with her camera, and would one day compile a remarkable book. Folk Songs and Folk Lore in South Uist is indispensable to all students of either.'

John Lorne Campbell was heir to the estate of Inverneil, at Ardrishaig. While at Oxford he had taken Gaelic classes. He had also corresponded with Mackenzie, who had urged him to come to Barra. After their marriage John and Margaret settled on Barra, not far from Mackenzie's new home. Margaret felt that, as an American, she had has been ''snubbed'' by the clique centred round Mackenzie's new house, where John Lorne, the Coddy and the parish priest went for billiards and conversation on a Sunday. Years later she stayed in Monty's study in Edinburgh while she waited for a train that would take her to Mallaig for the boat connection to Canna, the island the Campbells bought in 1938, and which they were to gift to the National Trust for Scotland.

''Monty looked at me and said: 'Margaret, you don't like me'. I said: 'You don't like me either.' We both laughed. I said to him: 'I can tell you one thing, though. You were the biggest inspiration and help to John. You made him work at his Gaelic recordings and the Sea League'. From that moment on Monty couldn't have been a better friend.'' In 1933 Monty and John Lorne had founded the Sea League, to fight for Hebridean fishermen's inshore rights which were being destroyed by the larger boats from England and the East coast of Scotland.

When I raise with Margaret her dear friend's connection with the aristocracy, she replies immediately: ''Monty hadn't a streak of snobbery in him. When I visited him at his house in France he was in and out of the farmer's house. In Edinburgh the woman who cleaned his house was dear Mrs Davies. It was absolutely astounding, the way he could get on with all classes. And, of course, he was a born actor. He was such an entertaining conversationalist, and he made everyone respond to him. They loved him. He had terrific charisma. He was totally unaware of it. He was completely unselfconscious.''

Margaret remembers when The Monarch of the Glen was being written. Monty records in Octave Eight under Fifty eight years old: 1941: ''With pain and irritation I found The North Wind of Love too much of a strain and took refuge as I have so often done in writing a comic book. This was The Monarch of the Glen.''

Margaret Campbell is laughing on the phone from Canna. ''I remember when I was going out on the boat to Lochboisdale, Moray McLaren was on the deck. I was talking about piping and mentioned a Highland lord's name. Moray MacLaren said: 'Hush, your American voice is like the oboe; you can hear it above all the orchestra. The man you've just mentioned is sitting over there, and he thinks he's Ben Nevis in The Monarch of the Glen'.''

Andro Linklater writes in his biography of Mackenzie: ''Although the original of Ben Nevis was confidently recognised in many of the Highlands' most prominent landowners - Cameron of Lochiel being the most popular choice, though Lochiel himself picked MacDonald of Glengarry - it would be truer to say that he represented a type whose traits are unusually well marked. Educated at an English public school and supported by a rich English wife, Ben Nevis is genially ignorant of his surroundings and his history. He retains some words of Gaelic from his childhood - ''always wish I'd kept them up'' - and a few legends of the MacDonald past, but his chief expertise lies in determining the order of precedence at the Glenbristle Highland Gathering, the likelihood of county council grants being available for the repair of his roads, and the prospects for grouse-shooting and stalking.''

But Angus Campbell of Dunstaffnage also gave Ben Nevis some of his endearing characteristics. When I was a boy and a new kilt came, Dunstaffnage would bury it in a bog for a year to toughen the fibres. Ben Nevis does the same.

Monty records with amusement Dunstaffnage once tried to persuade him that the origin of Campbell was the Italian Campo Bello, and not the Caimbeul, or ''crooked mouth'' in Gaelic.

Such was Monty's appeal as a novelist and personality that he could have married into the landed class. However, he chose as his second wife his Barra secretary Chrissie, the daughter of Malcolm MacSween who rented the grazing on the Shiant Islands. In 1959 Lily MacSween, Chrissie's younger sister, gave up her teaching career.

Monty invited her to open a hairdressing salon at his Drummond Place residence. Evelyn Waugh wrote with alarm: ''Someone told me a barber had opened up shop in your beautiful home. Surely not?'' Chrissie died in 1963. Two years later her sister Lily, who is still alive, became Lady Mackenzie. Both sisters gave him unstinting love and support.

In old age Angus Campbell of Dunstaffnage sat at my grandmother's fire, reminiscing about the days when his guests signed their names with a diamond in the drawing-room of his mansion.

''You remember how the Siamese cat Potipher which Compton gave us ran up into the wood after the fire and we never saw it again?'' my grandmother reminded him. The Marnichty of Dunstaffnage Castle, who would bury no more kilts in bogs, stared into the embers. ''Monty was wonderful,'' he said wistfully.

Monarch of the Glen continues on Sunday evening at 8pm on BBC1.