EVEN as old piggeries may go, the house at Detchant had seen very much better days. The windows were long shattered, swallows colonised the beams and the shepherd's dogs had taken over the living quarters. The pigs, for whatever reason, had moved out.

Probably, it took a very special sort of man not only to look and to think "potential", but to envisage, bricks from straw, a dream home there.

All of which explains why Lord Walton of Detchant may not just be the only peer of this or any other realm to live in an old piggery - and to live, if not like a lord, then in great style and comfort - but to proclaim on the nameplate his home's proudly porcine past. "It may sound rather quirky," he says, "but 25 years ago The Old Piggery is precisely what it was."

Detchant is an attractive hamlet just off the Al in north Northumberland, views eastwards to Holy Island and to Bamburgh Castle, in every other direction across verdant countryside.

John Nicholas Walton was born in Rowlands Gill, near Gateshead, on September 16, 1922, moved to Hobson Colliery (otherwise Pickering Nook) when his father became headmaster of the village school and to Spennymoor when Herbert Walton took over at Middlestone Moor school.

It was Middlestone Moor's closure at the end of the summer term which prompted Lord Walton to write, to recall happy days and to offer a reprise on the extraordinary dynasty that is the Waltons.

His grandfather had started down the pit near Consett as a ten-year-old, an uncle worked at the Ironworks, another was manager of Blackhill Co-op. None, not even his educated father, had much more medical background than the instructions on the side of a Syrup of Figs bottle.

Ernest Walton, John's younger brother, became consultant pathologist at North Tees hospital and still lives on Norton Green; Mary, their sister, became a GP, a medical missionary in Sierra Leone and medical director of the Runcie Hospice in St Alban's. Three of her children are all doctors, too. "I think Ernest and Mary saw my enthusiasm for medicine," says Lord Walton.

He'd been first to attend medical school in Newcastle, qualified in 1945, became one of the world's leading neurologists, held more high offices than a penthouse poltergeist, has more degrees than a Fahrenheit thermometer, occupies a corner of Who's Who so expansive that a supplement may shortly be necessary and recalls the first thing that he tried to teach his students: "The most difficult lesson in life is how to organise your time."

There is a story, indeed, of the senior meeting at which, unusually, he was unable to be present. "Apologies for absence," it was announced, "from the President of the Royal School of Medicine, the President of the British Medical Association and the Warden of Green College, Oxford. He's busy."

Middlestone Moor was an all-age school before the war, though - like his siblings - he passed the 11-plus to attend Alderman Wraith Grammar School, a mile along the road in Spennymoor.

"I think I knew I wanted to go into medicine even then. I was very impressed with Dr Davis, our GP, a very kind and interesting man, and read lots of popular scientific literature. My mother may have suggested I become a doctor, but it was my own decision and, in a way, it had grown up with me."

The family were also devout Methodists, in church three times every Sunday. Young John was persuaded to sign the pledge at nine, didn't touch a drop until mistakenly assuming at a New Year's Eve party 12 years later that all ginger wine was non-alcoholic, was forbidden even to ride his push bike on the Sabbath.

It was through Spennymoor Central Methodist Church, however, that he grew better to know Betty Harrison - "Harrison's the Bakers," he says - who not only played the chapel organ but was sports champion, victrix ludorum, in the year above him at Alderman Wraith. "I never thought she'd look twice at someone like me," insists Lord Walton, "then one day she asked me to carry her music home and I've been carrying it ever since."

They married in 1948, his £50 annual income as a junior doctor augmented by another £50 he'd won for passing an exam. It funded a ten-day honeymoon in Norway, with £4 spending money left over.

He'd first contemplated becoming a surgeon, though swiftly decided against it. "I soon realised I was too clumsy. I didn't have the manual dexterity but also, perhaps, I didn't have the patience. You really have to be very patient with a knife in your hand."

Now they also have a home in the Cotswolds, though it's in Detchant that they spend the summer, where Lady Walton brings coffee in Holy Island mugs onto the patio, where the postman still delivers huge bundles of scholarly magazines (Cerebellum, The Doctor, the American Journal of Medicine) and where he hopes, a little unconvincingly, to shed a little of the load. One year, Lady Walton had pointed out - "she looked at my diary" - he'd spent 169 nights away from home. When he became president of the World Federation of Neurology it was on condition that his wife came, too.

"The demands of my work mean that I may not have given as much time as a father to my children as I should have done. I was never there, either working or behind my desk until the small hours in my study.

"I have striven to put everything I can possibly give into what I have done. I regard myself as a dedicated patriot; despite all this country's problems, I love it."

After qualifying with first class honours, he spent almost all his career in Newcastle hospitals, became professor of neurology in 1958, Dean of Medicine from 1971-81 and was from 1961-66 a colonel in the Territorial Army. He was knighted in 1979, made a Life Peer ten years later, was for 25 years chairman of the Muscular Dystrophy Group of Great Britain, is a Freeman of both Newcastle and London, still lectures worldwide and has written many books including his 1993 autobiography, The Spice of Life.

"I have to have challenges," he says. "My mind needs something to occupy it."

His interests include sport, particularly golf - "I can still do 18 holes without too much difficulty" - reading and music, though it's Lady Walton who is both artist and musician.

"I took lessons for four or five years and can't play a note," says her husband, though in Oxford they are noted for their party piece Geordie duets - Blaydon Races a particular favourite.

Her music sits on the piano, much of the rest of the house taken up with pot pigs of every kind, bought mainly by friends.

They sit side by side throughout the two-hour chat, Lady Walton occasionally adding recollections, but generally content just to listen like she'd never heard the remarkable story before.

She's 80 now and manifestly they are greatly contented - as happy as pigs in clarts, as they might affectionately say in Northumberland, and every bit as at home.