A neat red-brick house on a modern estate in Suffolk, with trimmed front lawn and roses lining the path, is a far cry from Norman John Gillies' first home. He was born in St Kilda, the barren, rocky archipelago of four small islands. The outermost of the Outer Hebrides, 110 miles off the west coast of Scotland, it was cut-off by stormy seas for up to nine months of the year. In 1930, his family were among the last 36 people evacuated from the island, bringing 2,000 years of habitation to an end. St Kilda is now a nature reserve and world heritage site. And Norman John is the only person left with the memories of a true St Kildan.

"We lived at No 10. There were 16 cottages in a little semicircle on Village Bay," he remembers. Next door was Christine McQueen, his widowed aunt; a few doors away his uncle, Donald Gillies, with his wife and daughters; and at No 15, his granny, known as "The Uncrowned Queen of St Kilda" for her youthful good looks. Today, this nickname is carved on a plaque by her abandoned home – part of the information available to the few summer tourists who make it as far as the UK's only dual world heritage site – recognised for its natural attributes and its vanished culture.

As Norman John talks – both his names are always used – I realise that every second name he mentions is a relative. From great-uncles to half-aunts (though never by divorce as marriage was for life in this devout Christian community) he seems to be related to most of the island. By the evacuation there were only five surnames left in St Kilda, and two thirds of the population were called Gillies or MacKinnon. Not that your name mattered much; for centuries – perhaps millennia – this isolated community functioned much like one extended family.

"Everything was shared," says Norman John. "Each day [except Sunday, God's day] all the men met between house No 5 and No 6 for the morning meeting – later known as the St Kilda parliament – to decide what needed doing and who would do it."

He shows me an old photo of dour-looking men in wool caps, among them his grandfather and great-grandfather.

"When the men had been to kill the seabirds," he says, "they were put in a big heap and shared out." Not according to who had risked life and limb to collect them, but according to need.

Seabirds were the staple diet, killed in dangerous seasonal outings by Norman John's father and his peers, who climbed, via ropes, the vertiginous cliffs of St Kilda that rise up to 1,300ft above the sea. The birds were eaten fresh in summer and salted, when salt was available, or air-dried when it was not, in winter. Seabirds were plentiful; St Kilda has the world's largest gannetry as well as the most extensive fulmar colony in Britain. Norman John cannot recall the taste but says, "I must have eaten a fair few fulmars, guillemots, gannets and puffins."

A few vegetables – especially potatoes – were grown on the crofts, mostly by the women, who also milked a small herd of cows and did all the fetching and carrying. Sheep were grazed on the populated main island of Hirta and on the smaller neighbouring islands of Boreray, Soay and Dun. They provided wool for clothing and to weave into tweed. Money was rarely used and the tweed was bartered to pay land rent to the laird and obtain food supplies from the mainland. "Stores – including huge sacks of oatmeal – would arrive with the last boat of the year in August," says Norman John.

The St Kilda women worked much harder than the men – but the men's work was more dangerous. Even tending the sheep could be perilous.

Norman John was named after his mother's two brothers. They were among five men trying to land on Dun in a strong sea swell when their boat capsized. No St Kildan could swim. Norman John's grandfather was saved along with another man and one body was retrieved, "But not Norman or John's." Both uncles perished.

St Kilda could ill afford to lose able-bodied males. Already depleted by disease and emigration, by the 1920s the community was struggling to feed itself. Nurse Williamina Barclay, posted to Hirta at this time, was horrified by what she found. Well aware, too, of the limited medical service she could provide, she tried to persuade the islanders that the time had come to leave St Kilda. The younger adults were mostly in favour, the older ones against.

Young Norman John knew nothing of this. He remembers Nurse Barclay for teaching him his first hymn while she was treating burns he'd got when his young cousin, in a misguided jest, showered him with hot peat ash from the household fire. Too young to work with the adults ("like children over nine or 10") or to be in the tiny island schoolroom, Norman John roamed over Hirta. "We didn't have toys," he recalls. "We played hide and seek and ran free." There was no crime on the island – the community genuinely lived by the 10 commandments – and doors were never locked. His most vivid memory is of his mother standing on a high dry-stone wall beckoning and shouting to both ends of the island, "Tormod Iain" – Norman John in Gaelic – "Time for your dinner!"

In 1930, this carefree childhood was blown apart. In January, Norman John's mother, Mary, developed appendicitis. "There were no boats expected until June," says her son, "so the first thing was to try to get a message out by trawler." At the end of the month, a trawler called and the captain sent a message to Edinburgh. It was another two weeks, however, before the authorities finally sent the lighthouse ship to collect the patient. Norman John remembers his parents being rowed out to the larger boat: "I stood on the pier with my grandmother. I remember my mum with her shawl round her head waving to me and me waving to her ... And that's the last I saw of my mother."

His father returned alone. Norman John remembers missing his mother as he realised she wasn't coming back. For years he thought she had died of appendicitis but the story turned out to be more complicated: "On May 13 1930 my baby sister was born – I didn't know I ever had a sister until 1991. For 60 years nobody mentioned it – and on May 26 my mum contracted pneumonia and they both died. When the news got back to St Kilda that really put the tin hat on the evacuation and they all agreed that they would leave the island. "We left on 29 August 1930 – HMS Harebell took us off."

The houses remained unlocked and in each was left a Bible, one of them open at Exodus. "I was only five, but I remember running around [the boat] with the other children," says Norman John. "My saddest recollection is seeing half a dozen of the women standing at the rear of the boat, their shawls round their heads like my mother, waving goodbye to the island until it was out of sight."

"We landed at Lochaline [in Argyll] and there was a crowd on the pier – I suppose they had come to see these strange people. And I saw my first tree. There are no trees on St Kilda." He laughs: "Guess what job the Scottish Office allocated to the St Kildans? Working for the Forestry Commission!"

Norman John saw his first car that day too. Never even having seen a picture of one, "It was very strange being motored along to our dwelling."

The biggest shock for the St Kildans, however, was that they were split up. A community that had shared everything and known everyone was divided and housed miles apart. "My aunt, who later lived next door to us, found it very hard as she had nobody near. When strangers came to the door, she found it, shall we say, very overcoming."

Young Norman John, his father and grandmother were allocated a tiny house in Ardness a long way from friends, family and schools. John was not impressed. St Kildan men are no shrinking violets, and he wrote to the Scottish Office: "This home is worse than the cattle byre I had in St Kilda. I understood from Nurse Barclay that we were to be situated in better homes, but this is worse than a dungeon hole."

Remarkably, he got his way and his little family moved to Larachbeg into one of three large adjoining houses occupied by St Kildans. The neighbours were once again Uncle Donald Gillies and family and 10 MacKinnons. John settled into work for the Forestry Commission and his son went to school with his cousins and the youngest MacKinnons.

Grandmother Gillies, 64, like most of the older islanders, found the transition harder. "She was [already] 17 in 1882 ,when the first schoolmaster came to St Kilda, so she only had a smattering of English," says her grandson. She continued to spin and knit as if she couldn't get used to money. "When the man came to cut our hair she paid him in [knitted] socks and gloves."

"My grandmother would have preferred to stay on St Kilda, but she had to go with the majority," he adds, and she had her motherless grandson to care for. "Many times after the evacuation," he remembers, "she said to me in Gaelic, 'Norman John, I've done more for you than I've done for my own six boys.' I suppose she expected her sons to fend for themselves in St Kilda [whereas] she had to look after me ... She was very kind."

Fortunately, one of her sons, Neil Gillies, became the summer warden of St Kilda, so every year until the second world war, she would return with him to Hirta and "recharge her batteries". Her grandson spent the holidays with his mother's sister. Neither Norman John nor his father revisited their home in this way. John died in 1945 and his son made a new life in England, working in the building trade.

Towards the end of the war, Norman John, who was in the Royal Navy, was posted to Suffolk. At church in a neighbouring village, "I saw this nice young lady, 18 years old. We've been married nearly 63 years and we've got three children, 11 grandchildren and eight great-grandchildren." He smiles proudly. Most of the family live within a few miles, although the great-grandchildren are spread from High Wycombe to Australia.

Norman John never forgot his roots and in 1976 returned to St Kilda as part of a National Trust working party to renovate some of the houses in which his family once lived. "It was quite emotional for me to see where I was born, the house where I lived, and visualise the people on the street," he admits. "And to see the church. I remember [as a boy] sitting in the church. I couldn't sit still sometimes and my mother had to get me from the aisle."

In 2006, Norman John finally discovered where his mother is buried – near the hospital where she died in Glasgow – and erected a stone in her memory.

Does he ever wish he hadn't had to leave St Kilda? He snorts in gentle derision. No rose-tinted nostalgia for him: "My life has been tremendous. Much better than it could have been on St Kilda." He loves the place though, and has visited several times in recent years. His family has been to St Kilda too. His wife is smitten, and two of his children can't keep away. Norman John thought he had made his last trip back but is going again this year, in June, a month after his 87th birthday with his daughter Shirley.

The islands may no longer be home, but the neat modern house in Suffolk, where Norman John has lived and loved his family for 48 years, bears a simple name plaque at the front entrance. It reads: "St Kilda."

An updated edition of The Life and Death of St Kilda, by Tom Steel, has been published by Harper Press, £9.99