Fifty years on from its first transmission, we are still captivated by The Prisoner, writes Lynne Mortimer

Until I was in my late 20s, the only thing I knew about Portmeirion in Wales was that The Prisoner was filmed there. No TV drama series in my lifetime has ever had a real location that looked so much like a film set.

But this was just one of the weird and wonderful things about iconic series The Prisoner, which first screened in the UK 50 years ago, at the end of September 1967.

As a 12-year-old, the philosophical and Orwellian niceties of the get-inside-your-head plot didn't occur to me. Moreover, I was utterly terrified at the prospect of being chased and captured by a giant balloon. Sixties TV audiences seemed unconcerned by the surreal nature of a story of a British secret agent brought in to a 'holding camp' to test his loyalty.

The conspiracy that found Number Six incarcerated in an Alice in Wonderland, down-a-rabbit-hole parallel universe tested the credulity of all its fans in the most enjoyable way. Did I know what was really going on? No. In retrospect, do I know what was going on? No. Does it matter? No. It was devised against a background of the Cold War and the predominant theme is the individual versus the 'state' but I just thought it was a great story. Kafka in technicolour (though I watched in black and white).

If you asked me how many episodes there were, I would have guessed at, maybe, 30. I would have been wildly wrong. There were just 17. Like Fawlty Towers (just 12 episodes) its influence far outstrips its active life.

The Prisoner starred and was co-created by Patrick McGoohan and, according to Wikipedia 'combines spy fiction with elements of science fiction, allegory and psychological drama.'

The series follows an unnamed secret agent who is abducted and imprisoned in a mysterious coastal village resort, where his captors try to find out why he abruptly resigned from his job.

There was a US miniseries remake in 2009 but I discard it.

The original and best series begins in a London flat where a man (Patrick McGoohan) is packing his bags for a hasty departure but a knock-out gas is piped into his flat and he falls unconscious, waking up in a re-creation of his apartment in a mysterious seaside 'village' where he is held captive and put under constant surveillance. There is an intimidating bubble that recaptures or destroys (by squashing, I seem to recall) those who try to escape. No names, just numbers. Our hero, assigned Number Six, rails against this faceless identity with the most famous quote of the show: 'I am not a number, I am a free man.'

His prime combatant is Number Two (but who is Number One?) who tries many ways to extract information from Number Six, including mind control and indoctrination. The position of Number Two is given to different people. Number Six meanwhile, continues to try and find out who his captors are and to escape.

Among the famous faces who played Number Two were Leo McKern, George Baker, Eric Portman, Anton Rodgers, Patrick Wyngarde and Patrick Cargill. The voice we heard over the Village loudspeaker was Fenella Fielding. Other well-known names in the show included Peter Bowles, Rosalie Crutchley, Paul Eddington, Donald Sinden, Nigel Stock and Wanda Ventham.

The final episode, which we hoped would make everything clear, was baffling. I read that McGoohan, who wrote and directed it, went into hiding to duck the demands for an explanation from confused viewers. It was, however, the only episode to credit Portmeirion. A prior agreement with the Welsh village's architect meant that the location was not to be revealed until the very end.

It is 50 years since I watched the entire series, though I have caught the odd repeat on cable channels. It remains a cherished memory of the days when television was challenging, imaginative and innovative... except perhaps for that bewildering final episode.

And, er... who was Number One?