Revealed: What Peter Cook really *!@*! thought about cuddly Dudley

To millions of television viewers they will for ever be remembered as lovable Pete and Dud. But newly uncovered footage has exposed a darker side to the celebrated comic partnership of Peter Cook and Dudley Moore.

The never before screened excerpts, from the recording of a film about their notorious alter egos, Derek and Clive, offer a revealing insight into the simmering jealousies that finally drove their double act apart.

For anyone reared on the gentle mix of satire and song that characterised Pete and Dud's Sixties collaborations, the footage is likely to make uncomfortable viewing when it is shown for the first time this Christmas.

Focusing on the production of a little-known 1980 film made to accompany the last of the expletive-ridden Derek and Clive recordings, it features scene after scene in which Cook hides behind his character to mock his partner.

In one sequence, Moore is left so numbed by Cook's relentless barrage of four-letter insults that he places a top hat over his microphone and storms out of the studio.

Another revolves around an absurd argument about the use of the term "edit point" during the process of recording. When Moore, who at the time had just embarked on a lucrative Hollywood career, dares to suggest he understands what it means, Cook launches into a sarcastic tirade, sneering: "You don't know what an edit point is. You worked in movies, have you? Have you ever worked in movies? Who have you starred with? Tyrone Power?"

Eventually, an exasperated Moore turns to check the camera is still running, before spitting the pair's trademark "c-word" curse at Cook.

It is as the pair film the recording of their infamous "Mother" sketch, however, that Cook becomes most vicious. As a bonnet-clad Moore repeatedly struggles to make himself heard, his partner barracks him, finally roaring: "Why don't you shut your fucking face and die!"

While Cook appears to have the upper hand in most of the excerpts, there are times when Moore manages to outwit him. As the comics arrive at the studio, Cook tries several times to plant a kiss on his partner's face. Visibly reviled, Moore pulls away, before snapping angrily at the unseen camera operator and warning him not to make his "hooter look like Mount Rushmore".

In another scene, an off-camera Moore can be heard saying: "Breaking up is so easy to do!"

Not all of the footage used in the documentary is concerned with the deterioration of Cook and Moore's relationship.

Some of Cook's dialogue and actions seem to be more inspired by his bitterness towards his then wife. At the time of the recording, he had only recently been ordered by a court to stay away from her – while still living in the same house.

In one scene bordering on the sinister, Cook demonstrates how to deal with sarcastic-looking women by showing viewers how to punch a blow-up doll.

Though surreptitiously acquired pirate videos of the footage have long circulated in fan circles, its inclusion in a Channel 4 documentary to be screened on Christmas Day will mark its first public airing.

The film from which it hails, Derek and Clive Get the Horn, was refused a cinema release. When Cook subsequently attempted to bring it out on video, he was thwarted by James Anderton, self-appointed moral arbiter from Greater Manchester Police, who had it impounded.

More than 20 years later, Tony Moss, who produced the documentary, had to go to extraordinary lengths to secure the use of the excerpts he chose. Chief among the obstructions was Cook's widow, Lin, who he says threatened to do all in her power to dissuade other people from co-operating with the film.

Nonetheless, Mr Moss persisted, believing the footage to offer the clearest insight yet into the extent to which, by the early 1980s, a once glorious comic partnership had almost totally broken down.

"Dudley had gone to Hollywood and was making films like 10 with Bo Derek and Peter didn't like that at all," he said. "When Dudley came into the studio to record Ad Nauseam, the last Derek and Clive tape, he didn't even know that Peter was going to have it filmed.

"What you see on the film as a result of all this is an extraordinary level of malevolence between them."

He added: "Lin didn't like Derek and Clive, and she made it clear that she wouldn't co-operate with our film and would encourage others to have nothing to do with it.

"In the end, we were only able to use clips by citing the law of 'fair dealing', which says that you can review excerpts for artistic or cultural reasons. What we ended up having to do was to find interesting historical and cultural points to justify effectively breaching the copyright."

Not all of Mr Moss's chosen excerpts made it into the documentary. While it would doubtless have raised a smile, he failed to find any artistic justification for including a scene in which a young Richard Branson, who helped to produce the film, appeared on set disguised as a police officer. "He turns up dressed as a Special Branch officer, making out he is there to arrest someone," he said. "It's all rather surreal. He looks like a naff Jeremy Beadle."

Aside from the new footage, the documentary features meditations on the curious misanthropic charm of Derek and Clive from some of today's biggest comedy stars. Among those who contribute are the stand-up comics Jackie Clune and Johnny Vegas and Ricky Gervais, star of The Office, who says of their predilection for four-letter words: "The British lead the world in swearing. If it was an Olympic sport, we would win gold every time."

Others offer their own interpretations of the reasons for Cook and Moore's later mutual antipathy.

Harry Thompson, Cook's biographer, described how the star would systematically "attack" his colleague "under the guise of comedy". He cites a spoof rendition of "My Old Man's a Dustman" on a late Derek and Clive recording, which Cook uses to hurt Moore by mocking his father's death from cancer.

Danny Baker, meanwhile, suggests that Cook's lambasting of women is more likely to have reflected his sense of self-loathing than any deep-rooted misogyny.

Mrs Cook was unavailable for comment last night.

'The Real Derek and Clive' is on Channel 4 on Christmas Day at 10.55pm