As Festival No.6 returns to Portmeirion in north Wales, we celebrate the cult series that inspired it.

Next weekend, Festival No.6 celebrates its fifth anniversary in the village of Portmeirion, north Wales. It is an attractive setting, given the eccentric, Italianate architecture and beachside location. The annual celebration of art and music is inspired by the 1967 cult TV show The Prisoner, which was filmed there. Many people who attend the festival – especially the younger participants – would not claim to have seen the show that gave birth to it. Even less would care to discuss its significance.

If you are not familiar with The Prisoner, the fact it is often described as a spy series or a sci-fi show undersells it somewhat. To get a more accurate picture, you’d have to imagine Mr Harold Pinter writing a Jason Bourne movie directed by Mr Stanley Kubrick. When a British secret agent (Mr Patrick McGoohan) resigns from his post, he is kidnapped and spirited away to a mysterious and idyllic seaside resort called The Village from which there is no way out. This pretty prison is a retirement home for those like him who “know too much”. There are no names – only numbers. And each episode sees Number Six (Mr McGoohan) attempt to escape, while a series of authoritarian Number Twos, receiving orders from an elusive Number One, try to find out why he resigned. At the time, The Prisoner was the most expensive TV show ever made. When it aired, the last episode was so contentious (see below) that Mr McGoohan (who also created, wrote and directed the series) moved countries, in need of respite from disgruntled fans.

In 2009, the show was given a (somewhat unsuccessful) reboot by AMC/ITV. This year there have been rumours that Mr Ridley Scott is in line to make a film version. But the original remains, in hindsight, unique and way ahead of its time. Here are five reasons why.

The costumes, cars, and set design of The Prisoner are visually astounding: simultaneously quintessentially 1960s and somehow brilliantly timeless. The Village uniform – worn by all residents – is a deceptively friendly blend of colourful capes, piped blazers, chequered shades, striped sweaters and sneakers. If it hasn’t yet inspired a major fashion designer’s show, we’re not sure why. The iconic setting of Portmeirion blends pastel-columned exteriors with interiors of Le Corbusier furniture, lava lamps and egg chairs; while its metallic, minimalist subterranean sets could be straight out of a James Bond film.

Mr Patrick McGoohan famously turned down the role of James Bond because he disapproved of the emphasis on sex and violence and objected morally to the character. When TV was depicting women as giggly eye-candy and swooning love interests, The Prisoner completely eschewed romantic storylines. Uncharacteristic of the era, the show’s female characters are all fearsome antagonists and skilful spies – there isn’t a short skirt or flirtatious look in sight. These women are ruthless and cunning and without exception outsmart Number Six. Contrast this with the male Number Twos and their macho assistants who are weak and paranoid and, ultimately, frequently defeated.

In many ways, The Prisoner is a classic Cold War thriller: a secret agent taken to a prison run by one “side” or the other. However, its Cold War commentary is surprisingly progressive and unpatriotic. It points out the absurdity of war: in episode two, “Chimes Of Big Ben”, Number Six asks which side runs The Village, to which Number Two responds, “It doesn’t matter… both sides are becoming identical.” This is something that resonates poignantly today. The series also carried subtle anti-Vietnam War messages, playing “All You Need Is Love” over scenes of gunfire in the finale – one of the very few times The Beatles allowed their recordings to be used on TV. The Prisoner, often described as “Orwellian”, also scathingly foretells the role of intrusive surveillance in our lives (there is not an inch of The Village that isn’t covered by the gaze of a camera), an increasingly corrupt democracy and media spin.

The finale sees Number Six finally discover who Number One is. As reveals go, you would be hard pressed to find anything more jaw-dropping and head-scratching. It caused uproar among its audience who inundated ITV with irate calls demanding an explanation; and Mr McGoohan left London for Switzerland after its broadcast to escape the wrath of the viewers. But the reveal isn’t just a shock plot twist; it holds a mirror up to us, turning not only the entire series on its head, but also the way we view ourselves and the control we have over our own lives.

The Prisoner isn’t just a breathless, state-of-the-nation drama. It can be seen as a powerful allegory for a very contemporary fear. The Village, with its pocket democracy and capitalist economy, is a metaphor for society, while Number Six represents all of us fighting to maintain our individuality from forces that would rob it. The series asks us some uncomfortable philosophical questions. Are we really in control of our individuality? In episode five, “The Schizoid Man”, it challenges our physical attributes, our personality: in episode four, “Free For All”, it examines our freedom to vote, and throughout the series until the climatic Kafka-esque final two episodes “Once Upon A Time” and “Fallout”, where Number Six is locked into an almost impenetrable battle of words with Number Two, it asks if it’s our freedom of thought that makes us individuals. The series’ closing scenes show resoundingly that we all make our own Villages and we can never truly “escape”.

Festival No.6 takes place in Portmeirion, Wales, 1–4 September