Watch this: the return of TV's late-night funnymen turned into a bizarre mix of picketing and presidential politics as Republican presidential candidate Mike Huckabee appeared on Jay Leno's show on NBC and Clinton turned to Letterman on CBS.

Jay Leno, America’s top-rated television comic, has got himself into deep trouble by telling his own jokes.

The host of The Tonight Show on NBC returned to the airwaves without his 19 writing staff after a forced two-month absence because of the Hollywood writers’ strike.

The former stand-up comedian wrote all the material for the show himself – including the customary opening monologue of topical jokes.

“I am doing what I did the day I started,” he said. “I write jokes and then I wake up my wife in the middle of the night and say, ‘Honey, is this funny?’ So if this monologue does not work, it’s my wife’s fault.”

His candour provoked controversy as Hollywood insiders accused him of violating the strike rules. Leno, a member of the Writers Guild of America (WGA), has supported the stoppage, which was called to demand a greater share of revenues from DVDs and digital downloads of writers’ work.

Before Christmas he delivered coffee and doughnuts to pickets outside NBC’s studio in Burbank, California. On Wednesday’s show he said: “The writers are right. I am a writer. I am on the side of the writers.” He caused consternation by prewriting his jokes, apparently in violation of WGA regulations. The union says that members are barred from writing any material that would normally be written by striking writers.

Within hours Patric Verrone, the WGA President, told KPCC radio that the union would have to “talk to Jay”. The union issued a statement last night saying: “A discussion took place today between Jay Leno and the Writers Guild to clarify to him that writing for The Tonight Show constitutes a violation of the guilds’ strike rules.”

In contrast, Leno’s arch rival, David Letterman, returned to CBS after reaching a separate deal with the union. His show descended into a diatribe about the industrial action. His Top Ten became a catalogue of the union’s demands. Their No 1 demand was: “Producers must immediately remove their heads from their asses.”

To make matters worse Letterman wore a “strike beard” that he had grown during his two months off-air.

“Here’s the late-night lesson: good writing trumps no writing, but no writing trumps bad,” Robert Bianco wrote in USA Today. Leno beat the scripted Letterman by 7.19 million viewers to 5.6 million.

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