Beatrice and Tony Porter had never heard of Burgh Island when, on a November evening in 1985, a friend of their daughter rang them to say she had seen an item on local television about a Devon island that was up for sale, complete with a 1929 art deco hotel.

The Porters, who were working in London as fashion consultants, shared a passion for art deco architecture and the sea, so they jumped at the news. They scrabbled to raise the necessary loans, and managed to beat a snooker federation, a gay liberation group, a nudist club and an anonymous pop star in the rush to buy.

That winter, the Porters slept in their overcoats in Burgh Island Hotel, whipped by easterly gales and up to their necks in debt. But their suffering was worthwhile, for this Devon island hotel is one of the most intriguing and stylish in Britain.

It is reached by the country's only Giant Sea Tractor, a colourful pavilion perched on long sea-legs that carries passengers on fat tractor tyres along the causeway from the mainland. Burgh Island looks out on the glorious beaches of Bigbury Bay, has its own bird sanctuary, a wealth of rare flowers, and is crowned with the flamboyant hotel, designed 65 years ago by Matthew Dawson for the wealthy industrialist Archibald Nettlefold (the N in GKN).

Here, Agatha Christie wrote And Then There Were None and Evil Under the Sun; Edward, Prince of Wales, and Wallis Simpson came to escape the press, and Noel Coward to meet the right people. Here Geraldo sang, Harry Roy and the Mayfair Four played (on the diving platform in the centre of the Mermaid Pool), and guests knocked back martini cocktails in the brilliant white sun lounge, or dined in the Ganges Room (the captain's cabin of HMS Ganges, built in Bombay in 1821, and reputedly the Royal Navy's last sail-powered flagship, which juts out wilfully from the main body of the building).

During the Second World War, Burgh Island served as a military base, and in the late Forties the hotel reopened as holiday apartments, before sinking into a long and inglorious decline.

Before the Porters came to its rescue, however, it did enjoy a brief moment of stardom in John Boorman's first and largely forgotten film, Catch Us If You Can, featuring the Dave Clark Five. ' This, according to the publicity blurb from Warner-Pathe, was 'a high flying, free-wheeling firework of a film, as contemporary as tomorrow's headlines and twice as much fun'. Dave Clark, it said, had written 'a sparkling supply of new numbers, many of which have 'hit parade' written all over them'.

The songs failed to make the grade, and the film failed to make the Oscars. Halliwell's Film Guide pans it, although Dilys Powell, doyenne of film critics, was kind at the time of its release. Dave Clark also played a cameo role in Get Yourself a College Girl, but he was no Daniel Day-Lewis - no John Lennon, for that matter - and the Dave Clark Five were never going to be the next Beatles, despite topping the charts in 1964 with the stomping, drum-heavy 'Do You Love Me?', 'Bits and Pieces' and 'Glad All Over'.

Although spliced together from too many inconsequential bits and pieces, the screenplay of Catch Us If You Can (by Peter Nichols) has its moments. What there is of a story goes like this, according to the distributor's blurb: 'Steve (Dave Clark) and his four friends, Mike, Lenny, Rick and Dennis, are a young, enterprising and athletic group who have formed themselves into a company, Action Enterprises, and live in a converted chapel in London. While they are hard at work filming a television commercial (in Smithfield Market), Steve and Dinah (Barbara Ferris), the vital symbol of a nationwide 'Eat Meat' advertising campaign, decide to escape from the world of commercialism and visit the small island she wants to buy . . . islands, both real and imaginary, are the basis of this story of modern day youth . . . real, because they do exist; imaginary, because the ideals of total escape to one are just wishful dreams.'

The young Dinah - a Felicity Kendal look-alike in beret, striped T-shirt and leather skirt - reaches Bigbury Bay with Steve in tow. But the rat- like ad agency director has told Scotland Yard that Steve has kidnapped Dinah, and they are pursued by police. When the tide goes out, Steve and Dinah discover that Burgh Island is not really an island; it is attached to the mainland by a causeway which emerges at low tide. It was impossible to escape London, exploitation and the 'Eat Meat' campaign after all. Having led Steve a merry dance and promised him a world of fresh adventure, Dinah decides to abandon him on the beach at Bigbury Bay.

Given their limited acting ability, the Dave Clark Five could never have made a film as fresh as Dick Lester's A Hard Day's Night. But Catch Us If You Can, made when John Boorman was 31 and fresh from a spell in charge of documentaries at BBC Bristol, still makes you want to down tools, rent a Mini-Moke and buzz down to Bigbury Bay and Burgh Island. For the real stars of this Sixties period- piece are not Dave, the boys, or the girl, but the sets, costumes and locations. Swinging London (stiff with developers' cranes and criss-crossed by post-war buses), Bath (filmed, before the city was cleaned up; scene of a gratuitous fancy-dress party in the Assembly Rooms and Roman baths), and mysterious Burgh Island all steal the show.

Trying to follow Dave and the boys, 30 years on, by fast bike through central London to south Devon via Salisbury Plain (in a daft scene Steve, Dinah and a group of real-life beatniks are caught up in an army manoeuvre), was like travelling in a time machine.

Dave and Dinah make their escape in a white E-Type Jaguar, accelerating away from Smithfield (still London's main meat market) and along London Wall in the City. This was a favourite street for directors seeking shots of the new London: it looked ultra-modern with its steel-and-glass office blocks, elevated pedestrian walkways, and its dual-carriageway slashing through the fuddy-duddy Square Mile.

What was new then is already history. Those slim office towers, so admired by Sir Nikolaus Pevsner in his Penguin Buildings of England series, began to give way in the mid-Eighties, in the wake of the Big Bang, to huge Post- Modern blocks. Piccadilly Circus, round which Steve and Dinah zip as they head out west, has also changed almost out of recognition. Eros is still there, but the Circus is no longer true to its name: you cannot drive round it.

The most obvious changes since Boorman's film, however, are those on the journey out of London, as the E-Type dives under (and hurries over) the new Westway section of the A40, out along what I guess must be the A30 and A303 (the road through Salisbury Plain).

Did trunk roads really look so different 30 years ago? There were no Happy Eaters or Little Chefs for Steve and the boys in 1965. There were no yellow lines, few stretches of dual-carriageway, and no speed limit, despite the bizarre mix of a 140mph E-Type jockeying with Ford Thames Traders, Scammel Scarabs, Ford Prefects and Bedford news vans.

Many of Boorman's rural scenes have been suburbanised or otherwise tamed. Nevertheless, as you duck off the main road between Totnes and Plymouth, and cruise the last 15 miles south to Bigbury Bay, the years peel away.

Lanes, fields, river banks, sheep and beaches look much as they must have done when Boorman brought his cameras this way. And the biggest change of all - the transformation of Burgh Island Hotel from seedy rooms to glamorous seaside retreat - is as delightful as it is unexpected. It is a perfect place to end a long bike ride, to paddle hot feet in the cool Atlantic swell.

In the hotel itself, sandy feet, bikers' leathers and Dave Clark-style natty denim two- pieces will soon be banned. This year, Beatrice and Tony Porter are taking Burgh Island upmarket, with gourmet evenings and a dress code. If they are to succeed where Dinah failed in realising their island idyll, they will need the Noel Cowards and Wallis Simpsons of today. Catch it if you can.

(Photographs and map omitted)