The parrot died laughing

Forty years ago, Monty Python's Flying Circus changed the world's sense of humour as Messrs Cleese, Palin, Jones, Idle, Chapman and Gillam embarked on something completely different.

The cast members of the original Monty Python's Flying Circus line up on a beach. From left to right, John Cleese, Terry Gilliam, Terry Jones, Graham Chapman, Michael Palin and Eric Idle.

Forty years ago, an unheralded new BBC comedy show, Monty Python's Flying Circus, slipped into a Sunday night slot previously reserved for televised prayer services on British television. The revised scheduling alone should have alerted audiences to the fact that some serious social changes might be underway. Presented with a line-up of sketches that featured the Spanish inquisition, a dead parrot and the Upper Class Twit of the Year Competition, the viewers, or most of them, fell about laughing while generally avoiding the troublesome question of what it all meant.

When first-generation Python fans gather now, greying, and, perhaps, less convinced of life's unfailing ability to amuse, the talk is of how the programme "stood comedy on its head" or "changed the rules". In the sense that no show before it would have thought to send Mrs Premise and Mrs Conclusion, two pinafore-wearing provincial housewives, to Paris to ask Jean-Paul Sartre to settle an argument they had started in a launderette about the nature of existence, this was probably true. "Ooooh, don't ask him," Mme Sartre warns the ladies on arrival: "He's in one of his bleeding moods; the bourgeoisie this, the bourgeoisie that."

The five surviving Pythons tend to see their legacy differently. Not just differently from the fans, but differently from each other. Today, they have reached an age and position in life where they have become not unlike the people they used to make fun of. John Cleese is 70, and currently touring European concert halls to pay for his latest divorce; Michael Palin, 66, is the president of Britain's Royal Geographical Society; Terry Jones, 67, writes scholarly books about the Middle Ages; Eric Idle, 66, produces musicals while Terry Gilliam, 68, is still trying to make a Hollywood movie about his literary hero, Don Quixote. The sixth Python, Graham Chapman, died in 1989.

They were middle-class boys, brought up in places like Weston-super-Mare and Melton Mowbray, the rigorously-educated sons of Rotarians, and mothers who went to coffee mornings and who never imagined that the social petrifaction of post-war England, with its reassuring conceits and certainties, would ultimately provide their children with a weapons-grade source of satire. "The culture at that time was stuffy," says Cleese. "It was like wrestling with a sponge. I remember going to see Beyond the Fringe in 1962, and hearing screams of laughter. They were screams of liberation."

Hard-core Python fans are prone to give the impression that the show came out of nowhere - an act of miraculous deliverance from the cosy sitcoms, Whitehall farces and "put-your-teeth-in-granny" radio comedies of the early 1960s. As though, one day, you were watching Thora Hird and Freddie Frinton in Meet the Wife, and the next you had Pablo Picasso completing an oil painting while riding a bicycle along the B2127 between Ewhurst and Dorking

It wasn't quite like that. Monty Python's ebullient anarchism grew out of the fissures in the social landscape that were already allowing a new kind of comedy. It was radical, unfettered by notions of deference, and political in allusion if not content. The touchpaper was arguably lit a decade earlier by the playwright John Osborne, with the opening of Look Back in Anger, but comedy was quick to recognise the new opportunities, and Beyond the Fringe, a razor-sharp, authority-mocking stage revue mostly written by Peter Cook, took up the challenge, as did That Was The Week That Was, a groundbreaking TV satire programme starring David Frost. Both were immensely influential on the future Pythons.

The coming together had begun at university. Cleese, Chapman and Idle were Cambridge men; Palin and Jones had been at Oxford. Only Gilliam, a laid-back American who had moved to Britain to work as an animator, hailed from outside the class mould. Some years later, in A Fish Called Wanda, Cleese's character was given to plead: "Do you have any idea what it's like being English? Being so correct all the time, so stifled by this dread of doing the wrong thing. We are all terrified of embarrassment. That's why we are all - dead!" It was exactly this sense of repression that gave the Flying Circus its lift-off.

The individual Pythons had written and performed for their university drama groups. Intoxicated by the whiff of escape from the professions their parents had mapped out for them, they had moved to London, and found work on the burgeoning new radio and television comedy programmes that were already pushing at the limits of the possible. The Frost Report, on which they all worked together, was an instant success. But Frost was a man of boundless vanity whose name, in enormous letters, would dominate the show's credits while those of the writers flashed past. It was time to launch the next stage of the revolution.

The BBC agreed, at the urging of star producer Barry Took, to give the proto-Pythons a show of their own. Terry Jones recalls: "When we went in all the executives asked: 'Well, what's the show going to be about?', and we said, 'Well, we don't know'. 'Well, who's it going to be aimed at?' 'Well, we don't really know'. 'Is it going to have music in it?' 'Well, we don't really know.' 'Well, what's it going to be called?' 'We don't really know,' and then they said: 'Well, we can only give you a budget for 13 shows'."

The first episode was screened late on a Sunday night, and opened with a long-distance shot of a ragged, wild-haired man staggering from the sea. Collapsing on the shore he gasped one word: "It's-", followed by the voice-over "Monty Python's Flying Circus". For the next half hour a previously-unimaginable torrent of surrealist absurdity poured forth - Mozart presenting a television documentary about famous people's deaths, the funniest joke in the world that no one can hear and live, an interview with composer Arthur "Two Sheds" Jackson.

The BBC was baffled. "Every now and then," recalls Palin, "they would take us off, and run The Horse of the Year Show instead. But it meant that we could plod away unnoticed. Plotting more outrageous things. After about two or three shows, it was clear there was a cult developing. There were people who liked it because so many other people didn't." Looking back, it is possible to spot, beneath the patina of madness, some of the ways in which the Pythons changed comedy. They did away with the idea that a sketch needed a beginning or an ending. Often Python sketches didn't end at all, but were terminated by Chapman, dressed as an army colonel, declaring that things were getting "far too silly". Other ways of concluding sketches were to have a 16-tonne weight fall on one of the characters or for Cleese to interrupt proceedings with: "And now for something completely different."

They mixed animation with live action, put heterosexual male actors into women's clothes, established the idea that a troupe of performers rather than a single star can carry a comedy show, and, with sketches such as the "summarise Proust" competition, reconciled the infantile with the highbrow. The question always asked of elderly comedy shows is: would it still be funny now? In the case of Monty Python a more pertinent one might be: Would it still be allowed?

There's no doubting the show's pre-political correctness era credentials. The rules at the University of Woolloomooloo, where the entire Department of Philosophy faculty is made up of brawny Australians called Bruce, run as follows: "Rule 1: No poofters. Rule 2: No member of the faculty is to mistreat the Abos in any way whatsoever (if there's anyone watching). Rule 3: No poofters." Then there's the Silly Olympics, where a core joke is the inability of the deaf competitors to hear the starting gun.

Less amusing is the real life story of the strained relations between the Pythons. Three years ago, Palin published his diaries of The Python Years, blowing apart, in the process, the fond notion that the show had been created by lovably like-minded pranksters. Around the team, it was revealed, swirled an often poisonous atmosphere of jealousy, resentment, egomania and intrigue - much of it centring on Cleese's dominant role - that in effect ended the collaboration.

While the 40th anniversary sees the surviving members joining up in New York to discuss the show's history, none of them is interested in working together again. And that legacy? "The one thing we all agreed on," says Jones, "was to be totally unpredictable, and never repeat ourselves. We wanted to be unquantifiable. That we are now an adjective in the Oxford English Dictionary means that we failed utterly."