The corner of Wales that is forever Italy

It was always a fantasy, as unnerving and dislocating as the place itself.

"Where am I?
In The Village.
What do you want?
Information.
Whose side are you on?
That would be telling ... We want information. Information!
You won't get it.
By hook or by crook, we will.
Who are you?
Number Two.
Who is Number One?
You are Number Six.
I am not a number – I am a free man!"

The dialogue is from the opening sequence of one of the most cult offerings in the history of television, the 1960s cross-genre sci-fi fantasy psychological thriller, The Prisoner. The location was the village of Portmeirion, a wild whimsy of Italianate towers and Palladian façades emerging from a forest of giant rhododendrons in Penrhyndeudraeth, in northern Wales, where the mountains of Snowdonia bend to touch the waters of Cardigan Bay.

This week, after years of speculation, it was finally announced that a second series of the seminal television programme is to be made with the original star, Patrick McGoohan, making a cameo appearance at the age of 80. The location is being kept secret (Libya is rumoured) but wherever and whoever is involved (Russell Crowe, Mel Gibson, Christopher Ecclestone and Sir Ian McKellen have all been mentioned) there is a sense in which Portmeirion will remain the central character.

Portmeirion has always been more than a mere place. Indeed it existed in the imagination of a six-year-old Victorian child many years before the first foolish buildings began to rise from the coastland. Sir Clough William-Ellis first began to plan Portmeirion at the age of five or six when he had already decided to become a planner of towns. "Some day, somewhere," he later wrote in his book Portmeirion: The Place and its Meaning, he knew that he would erect a group of buildings which would be "an ensemble that would body forth my chafing ideas of fitness and gaiety – and indeed be me".

If there is a vague mysticism about that, so too was there about Patrick McGoohan's conception of The Prisoner. At the time McGoohan was the most sought-after – and highest-paid – actor in British television, churning out series after a series of a blockbuster called Danger Man (which was renamed Secret Agent for the United States). But he was bored with the role and proposed something new to the television impresario Lew Grade.

On the surface, it sounded attractively similar. He was to play a British secret agent who, after abruptly resigning from his position, finds himself trapped in an attractive village where everything is bright and cheerful – the people, their clothes, the buildings, the flowers. But behind the benign exterior lurks a more sinister purpose. His every attempt to leave the idyll is foiled by interrogators determined to discover the reason for his sudden resignation from the world of espionage. Everyone, he discovers, has no name, only a number. Lew Grade signed the cheque.

Though the show ran for only 17 episodes, it broke new ground with its elliptical, ill-defined sense of menace and depiction of a world in which a gallant loneindividual was pitted against the system. It chimed in acutely with the new era which was the Sixties. The location which McGoohan chose for The Village was Portmeirion.

Aptly, the place was like a physical correlative of the state of mind which McGoohan – who was the executive producer as well as the star, and himself wrote several of the episodes – had conjured. It was a fantasy made incarnate, and yet never fully realised. The vision was one which Williams-Ellis, in his later years, pronounced could not be put into words. Had that been possible, he said, he wouldn't have needed to build it.

Five decades on from the commencement of work – which was begun when he returned from distinguished service in the First World War in the 1920s – it was still not complete. And yet when the eccentric architect saw a preview of McGoohan's ingenious and mysterious television series at the local cinema he pronounced that "Portmeirion itself seemed, to me at least, to steal the show from its human cast".

The gardens in which the buildings grew had been cultivated since Victorian times. There are specimen conifers, Wellingtonia and Himalayan Firs, that date from that period – and a tulip tree, a massive variegated sycamore and a weeping silver lime which scents the village in August. Rhododendrons, camellias and a massive magnolia were added in Edwardian times.

But when Williams-Ellis acquired the land in 1925, the peninsula was a neglected wilderness with an old mansion surrounded by impenetrable vegetation. It became the centrepiece of a fantasy village, which strangely juxtaposed styles and buildings, with the intention of engaging visitors with interesting views wherever they should stop.

Some buildings he designed himself. Others – like the 1760 Old Bristol Colonnade, which stands in front of the domed Pantheon or the unique barrel-vaulted 17th century Jacobean ceiling in the Town Hall – were salvaged from original locations and painstakingly disassembled and reassembled in Portmeirion. The result, paying tribute to the atmosphere of the Mediterranean, is what one architectural commentator called "the finest, most elaborate, imaginative and sustained piece of folly work in Great Britain".

By the Sixties its bold pastel-washed façades looked extraordinarily fashionable, as if they had been painted by Mary Quant. It was the perfect setting for the bright attractive façade behind which the Kafkaesque menace of Patrick McGoohan's world lurked. This was a time when the paranoia of the Cold War vied with the psychedelic self-confidence of Sixties pop fashion and music. McGoohan's odd hybrid of sci-fi, spy-thriller and psychological study played to all that.

It had hi-tech action, an ineffable sense of conspiracy and a sense of doomed defiance against the shifting power of governments, multi-national companies and the world's militaries. Its political allegory was imprecise but it plugged into something potent about the relation of the individual to society. It satirised those who held power in Western institutions. And its brainwashing, hypnotism and thought-control experiments chimed in with the hallucinogens of a druggie era.

McGoohan leaned into all that. His sets may have been futuristic but his philosophy was decidedly contemporary. "We're run by the Pentagon, we're run by Madison Avenue, we're run by television, and as long as we accept those things and don't revolt we'll have to go along with the stream to the eventual avalanche," he said in one contemporary interview. "As long as we go out and buy stuff, we're at their mercy. We're at the mercy of the advertiser and of course there are certain things that we need, but a lot of the stuff that is bought is not needed ... We all live in a little Village ... Your village may be different from other people's villages but we are all prisoners." It was elliptical and apocalyptical all in one go.

The fans for whom it became, and remains, a cult loved it for that. Even this month Portmeirion has been home to the 2008 annual convention of Prisoner obsessives, who call themselves the Six of One group. Six was McGoohan's number in the Village, chosen, he later said, "because it is the only number that becomes another number when turned upside down".

Forty years on, fans still pore avidly over the show's details, decoding the opaque meaning of the scripts – even though Pat Jackson, now aged 92 and one of the series' directors, has recently revealed that, at the time, no one involved in the production knew what any of it meant either. This is a proper religion; online the adepts argue about which scripts, episodes, unpublished footage and details are "canonical". Such is the genius of ambiguity.

There is madness in the virtuosity of William-Ellis, too, with his pastel-hued confection of Italianate towers and neoclassical colonnades. It is not great architecture but it is far more than mere whimsy. Portmeirion has an artistic potency which has, over the decades, attracted a host of artists, of varying talent, to reflect in its glory.

Noel Coward often stayed at Portmeirion, and in 1941 – during the building moratorium which the Second World War forced on William Ellis – wrote his play Blithe Spirit there. The same year Michael Redgrave filmed H G Wells's Kipps there. In 1958, Ingrid Bergman was there to make Inn of the Sixth Happiness. In 1981, Jeremy Irons appeared in parts of Brideshead Revisited there. Robert Lindsay did Citizen Smith, Ronnie Corbett filmed Sorry, the sitcom Bread went on location and in 2002, the final episode of Cold Feet was filmed at Portmeirion with Adam (James Nesbitt) scattering Rachel's ashes into the Dwyryd estuary.

Through it all there have been constant rumours of the return of The Prisoner. The possibility was always there, like the unspoken bluff and double-bluff of the original series' scripts. "We have heard about a Prisoner remake off and on for the past 10 or 12 years," says Portmeirion's managing director, Robin Llywelyn, "but nothing has come of it to date. In 1997, things seemed to be progressing and we had some correspondence with Mr McGoohan about a Hollywood blockbuster."

The new ITV series is as definitive as anything ever is in the kaleidoscope reality that is the world of The Prisoner. It may well, of course, in this day and age be filmed somewhere a good deal more exotic if less substantial in its fantasy than Portmeirion.

Robin Llywelyn is not that bothered. Either way, he says: "The Prisoner is an important part of Portmeirion's heritage and we are proud to be associated with the series. It brought the village to a wider audience and has brought people to Portmeirion who would never otherwise have heard of the place."

And even as art follows life so life follows art. Portmeirion today has real-life 24-hour CCTV surveillance just as The Village did back in the Sixties.

Sir Clough Williams-Ellis, who died in 1978, would have had a response to that. "Portmeirion," he once concluded, "is intended to speak for itself."