What were you doing when you heard JFK had been shot? Watching Dr Who, most probably. It is 40 years since television's longest-running science-fiction series began, hours after President Kennedy was assassinated, and this month the National Film Theatre is celebrating the Time Lord's 40th birthday with a summer season of vintage British TV sci-fi.
Mainly it's a good excuse for a spot of televisual nostalgia, like watching TOTP2 on BBC2 and remembering how young you were when you heard the songs the first time around. Yet this jolly retrospective does something more than that - something culturally quite intriguing. Covering three decades, from the early 1950s to the early 1980s, it shows what a dynamic medium British television used to be for science fiction, and how well this denigrated genre captured the troubled spirit of its times.
Costume dramas tell you far more about the time when they were made than the time in which they are set, and the same is true of sci-fi. These trash-aesthetic shows claimed to describe some vague vision of the future, but they were actually remarkably accurate portraits of their own age. Back then, they seemed like far-fetched fantasies about alien invasion. Now they read like highly plausible allegories of impending nuclear war.
The TV Sci-Fi season at the NFT straddles the most perilous period of the cold war, and the arms race that fuelled it also fed science fiction. There is no artistic inspiration quite like imminent Armageddon, and just as medieval painters daubed gory images of Judgement Day on cathedral walls to terrify (and titillate) the faithful, science fiction revelled in the dramatic potential of the apocalypse to come. Some of its predictions proved uncannily prophetic. The 1961 Armchair Theatre television drama The Ship That Couldn't Stop, about a nuclear-powered liner set on a collision course with New York, plays like a dreamlike foreboding of the Cuban missile crisis the following year.
Even more revealing is the way sci-fi depicted Britain's shrinking status in this superpower stand-off. In I Can Destroy the Sun (1958), another fine Armchair Theatre production, Britain is still a leading player on the world stage - an honest broker knocking Russian and American heads together in the corridors of Whitehall. By 1963, when Dr Who began, Britannia had been demoted to the humble role of bumbling private eye. Like James Bond, but without the sex appeal, flashy gadgets or fighting prowess, Dr Who is a one-man band - alone, outgunned and outnumbered, a lot like Britain after Suez.
Every detail of Dr Who is infused with the wry self-mockery of a former champ who knows his finest hour has passed. This was Britain's postwar position personified, and the contrast with American sci-fi serials, such as Star Trek, is stark. Captain Kirk's Enterprise is a state-of-the-art starship, a virtual aircraft carrier bristling with weapons of mass destruction. Its vast crew is ostensibly international yet essentially American (sound familiar?), dishing out US-style democracy to strange new worlds, whether they want a dose of it or not.
Britain's Dr Who, on the other hand, was forced to slum it in a Tardis (Time And Relative Dimension In Space, in case you need to ask). It was like some useless British Leyland banger. Even with the Daleks in hot pursuit he could never get the bloody thing to start, and when he did finally manage to crank it into action, its faulty navigation system frequently dumped him on the wrong planet, in the wrong galaxy, on the wrong side of the universe. Indeed, the only thing this souped-up police box had going for it was that it was bigger on the inside than on the outside, rather like Britain's postwar role.
As Britain's influence on foreign affairs withered, Dr Who became bogged down by domestic strife. "The miners are on the point of armed rebellion," he warned the queen (not Her Majesty) in 1974. "It is wrong to give in to the miners," she declared, sounding uncannily like Margaret Thatcher. "They'll want more and more." Even the serial itself was a victim of industrial un- rest - a six-part story written by Douglas Adams was scuppered by a technicians' strike (remember them?). A screening of the surviving footage, catalogued by John Oliver of the British Film Institute, is one of the highlights of the NFT's season.
The one high-tech thing Dr Who could do was "regenerate" into different actors, and each actor who played him epitomised an era. William Hartnell (1963-66) portrayed him as a crotchety professor, barking orders at his obedient underlings, such as the future Blue Peter presenter Peter Purves. Such blind servility may seem bizarre by today's standards, but Dr Who was forged in the white heat of the technological revolution (Harold Wilson made his "white heat" speech at the Labour Party conference just a month before the first episode), and we still looked up to scientists then and quite liked them to boss us about. "I tolerate this century but I don't enjoy it," said Hartnell, sounding more like Lord Home than Wilson, with the weary resignation of an elderly Britannic Time Lord presiding over a rapidly evaporating empire.
Patrick Troughton (1966-69) depicted Dr Who as an impish, mop-topped sprite, like the Beatles' trendy uncle, while Jon Pertwee (1969-74) gave him the foppish allure of a Swinging London socialite, in ruffed shirts and crushed velvet, like a planet-hopping Jason King. But it was Tom Baker (1974-81) who hit the intergalactic jackpot, playing him as a dippy hippy with an unfeasibly long scarf, a fondness for jelly babies and just a dash of Sherlock Holmes. "All that was required of me was to be able to speak complete gobbledegook with conviction," he wrote in his autobiography, Who On Earth Is Tom Baker?. But it was this conviction, in the face of some spectacularly silly aliens, that made him an icon. Baker's Dr Who was camp, irreverent and forever teetering on the brink of catastrophe - a lot like Britain in the 1970s.
Off screen, Baker enjoyed a colourful social life entirely in keeping with his garrulous TV alter ego, hobnobbing with Soho characters such as Francis Bacon, Dan Farson and Jeffrey Bernard in legendary bars, including the Colony Room, the French House and Bernard's local, the Coach and Horses. "When I was doing Dr Who in the 1970s," Baker told Bernard's biographer, Graham Lord, "I spent an enormous amount of time with Jeff."
Conversely, Peter Davison (1982-84) reflected the new conservatism of the 1980s, creating a clean-cut Time Lord who could easily have sauntered straight off the set of ITV's 1981 adaptation of Brideshead Revisited. But from then on, the Doctor's regenerative powers began to wane. The Dr Who scribe, Douglas Adams, cultivated a hipper audience with his Hitch-hiker's Guide to the Galaxy, and even though Colin Baker (1984-86) and Sylvester McCoy (1987-89) both turned in lively performances, they never really matched their predecessors' cult appeal. From the late 1970s to the late 1980s, the ratings shrank from 14.5 million to 4.5 million. In 1992, the series was shelved and, despite a huge fan base on both sides of the Atlantic and a feature film starring Paul McGann in 1996, it remains in cryogenic limbo.
I hope the BBC never brings back Dr Who - not because I'm no big fan, but because I am. The way I see it, it's been downhill since Tom Baker hung up his hat and scarf, and its home-made monsters belong to an earlier, more innocent age. You won't catch modern children hiding behind the sofa from these costume cupboard cast-offs. Even the Cybermen would be lucky to raise a shriek from today's computer-hardened kids.
By far the best place for Dr Who is at the National Film Theatre this summer, sharing pride of place with forgotten gems such as the BBC's ambitious 1981 adaptation of John Wyndham's Day of the Triffids. And if you can't get along to the NFT, there is plenty to see on video or DVD. Although many of the early episodes were wiped, along with countless other classics, as part of the corporation's parsimonious policy of recycling old master tapes, there is still enough stuff out there in cyberspace to satisfy all but the most obsessive fan. And as for those cynics who say sci-fi fans are arrested adolescents, too frightened to tackle the real world, the best response I ever saw was on a T-shirt at a Dr Who convention in Denver (I only saw it on TV, you understand): "Reality," it said, "is for people who can't face science fiction." The late, great Time Lords Hartnell, Troughton and Pertwee would doubtless have agreed.
TV Sci-Fi is at the National Film Theatre, London SE1 (020 7928 3232) from 5-27 August