In the late 1950s, class was a major British preoccupation, with 'deference' still vigorously alive.

So an invitation from a titled school friend, the Honourable Edward Gully, to stay on his parents' Scottish island could only be exciting to the 12-year-old me, not just because islands were romantic, but because staying with a viscountess might be my 'open sesame' to a glamorous world. This was a time when Harold Macmillan's cabinet was stuffed with peers, and when pictures of partying aristocrats filled the pages of glossy magazines.

Until Faber & Faber recently decided to re-issue, along with the rest of my fiction, my first novel, For Love Or Money, I had not thought about my island holiday for ages. Yet my literary debut - written when I was at Oxford, and published in 1967 when I was 21 - had been loosely based on what had happened on the island in that summer of 1958. In fact, if I had chosen instead to complete the predictable university novel, which I had been working on for a while, I might never have found a publisher, nor have possessed enough grit to try again after the inevitable rejections.

Why did my mother let me stay on a remote island with people she didn't know? She had every reason to mistrust aristocrats. Both her long dead parents had been titled, and she had been dropped by her self-satisfied relations when she had married my father, whose undistinguished family owned an ailing transport business. My mother never talked about her aunts' out­rageous snobbery, but I knew she had been hurt. Even so, I suspect she decided to let me go because of an irrational fear I was missing out by never meeting the kind of people she no longer mixed with.

My social loss did not worry me at all. In fact, because she and my father were unhappily married, I was more interested in staying with parents who loved one another, than with parents who were posh. Sadly, my fantasy of chatting happily with the devoted Lord and Lady Selby in their island Shangri-La fell apart as soon as Eddie and I were tucked up in the Oban-bound sleeper. Above the usual cacophony of train noises, he muttered from his top bunk:

"I should have told you that my father doesn't live on Shuna any more."

"Bad luck."

"Mummy has a friend," he added, letting this statement rest in my mind for a moment. "His name is Donny, and he's almost a member of the family."

When we reached the island after chugging across the mile-wide strait in a small motor boat, I found Donny was dark haired, broad shouldered and perhaps 10 years younger than Eddie's mother, Lady Selby. She plainly doted on this 'friend', giving him playful little kisses whenever she was near him. He, by contrast, seemed disinclined to touch her. No wonder Eddie had sounded embarrassed. Of course, I knew that people who were married sometimes had 'friends', indeed my father had had one, who had caused my mother great grief, but he had never behaved like this when with his 'friend' - or at any rate not when I had been around too. But Eddie had to endure all this 'soppiness' every day.

The battlemented castle shocked me too. Though barely a century old, many of its corridors and rooms had been bricked up, and the family had already retreated to the core of the house: the kitchen, dining room, 'saloon' with baronial panelling and antlers, and five or so bedrooms, most with tattered curtains and windows that would not shut. There were no gardens, only a rough encircling lawn, pitted with rabbit holes and dotted with islands of rhododendron. The family waged constant war against the rabbits, shooting far more than they ate. Our meals were very simple, lunch often being bread and jam or cheese - 'a piece' in the local argot. Rabbit usually featured in our evening meal. From my first day, I tried to avoid thinking about how dis­appointed my mother would be if I wrote her an honest letter.

One evening after Donny and Veronica had been dancing to gramophone records for hours and drinking steadily, they had a serious row, which ended with Donny announcing he was leaving her. It had been raining all day and everyone felt trapped and tetchy. Veronica accused Donny of ingratitude and he yelled he had been wasting his life with her for too long. He had taken part in the D-Day Landings and said he hadn't settled to anything worthwhile afterwards because she had brought him to Shuna. When Donny hurried away from the castle carrying a suitcase and wearing oilskins, Veronica started to weep in gasping sobs. "I don't want to wake up in the morning," she moaned to no-one in particular.

When she appeared an hour later, much drunker, with a shotgun in her hand, I thought Eddie or his brother would try to disarm her. Instead, they backed away towards the door, taking me with them. They found a bedroom with a solid mahogany door and a functioning lock. As driving rain battered the windows, we listened keenly for footsteps outside our door or for a single shot. None of us slept. In the morning Donny returned, soaked to the skin, having failed to get the engine of the boat started in the storm. A reconciliation of sorts took place but the atmosphere between the two of them remained tense until my holiday ended.

The plan had been that two weeks later Eddie would come and stay with me, in my parents' Cornish cottage. But now he claimed he was not well enough. I did not blame him. By the time he arrived he must have guessed I was going to have given my parents a blow by blow account of the night on which Donny had threatened to go. Everything had become too embarrassing. We had left our Sussex prep school three weeks earlier and, as it happened, were destined never to see one another again. My mother rapidly dropped the subject of my holiday. Long before pop stars, footballers and supermodels had become the new aristocracy, she had lost all interest in titled people.

And what became of the dramatis personae in the end? Donny I imagine (though I may be wrong) made other bids for freedom and one day didn't come back. Veronica definitely left Shuna in the 1970s and survived into old age. On his father's death, Eddie inherited the castle and the island, although his older brother, Michael, succeeded to the title. Eddie and his wife and two sons lived on Shuna throughout the 1970s but abandoned the castle in 1985 when the roof fell in. Books, furniture and other possessions were never removed. He now farms on Shuna but lives on a neighbouring island.

Michael, who was at school with Eddie and me, died in 1997 at the early age of 54 and his son Edward became the 5th Viscount Selby. The young lord worked briefly in finance and latterly - according to the Glasgow Herald - as a checkout operator at the Tobermory Co-Op on the Isle of Mull. He died in a car crash in 2001, aged 33. His eight year-old son, Christopher, then became the youngest peer in Britain.

Eddie's great-grandfather, William Gully, the first Lord Selby, had been Speaker of the House of Commons in the 1890s. He is said to have spent £300,000 on building Shuna Castle - £30 million in today's money.

The fate of his family seems to underline the hard truth that when no new earner of money appears on the scene and when 'influence' and 'string pulling' cease to be effective, one outstanding person's achievement is unlikely to keep a whole succession of his descendants afloat forever.

Queen Elizabeth I's hard-headed Secretary Of State, Lord Burghley, suggested that "aristocracy is nothing but ancient riches", and the subsequent history of the Gully family would certainly seem to bear out the truth of his maxim. Money lay at the heart of my youthful novel, as love did too, in a tragi-comedy a lot sunnier and funnier than the bleak events which unfolded decades later.

Tim Jeal's novel For Love Or Money has just been re-issued by Faber & Faber, along with his next two novels, the third of which won the Llewellyn Rhys Prize. He is best known for his memoir Swimming With My Father, for his biography of Sir Henry Morton Stanley (Sunday Times Biography Of The Year) and for Explorers Of The Nile.