Barry Cryer has criticised today's sitcoms for lacking believable characters.
Cryer, 79, said that writers had forgotten how to create people who viewers could identify with and wrongly focused on making jokes.
He told the Radio Times: "We're living in an era of back-to-basics sitcoms and it's no laughing matter. From Vicious to Mrs Brown's Boys to The Wright Way, the old-fashioned situation comedy is suddenly all the rage again.
"It's a serious business writing comedy. You don't necessarily need funny lines all the time. The key is to create characters. Characters people can identify with. But right now we've gone back at least 30 years in terms of format."
Cryer, who penned jokes for Jack Benny, George Burns, Tommy Cooper, Les Dawson, Kenny Everett, Bob Hope, Spike Milligan, The Two Ronnies and Morecambe and Wise, said that ITV sitcom Vicious, about a bickering gay couple, should have been "fantastic" thanks to "two great actors" in Sir Ian McKellen and Sir Derek Jacobi.
He told the magazine: "But it was insult, insult, insult every other line. You don't believe in them. You don't like them, for a start. It was positively homophobic! It made John Inman look restrained."
He added: "The great sitcom writers of the past didn't think jokes were remotely important. Ray Galton and Alan Simpson, who wrote Hancock's Half Hour and Steptoe and Son, knew that instinctively. Johnny Speight who created Alf Garnett never did jokes; he just wrote great characters. And for immaculate writing it would be hard to beat Dick Clement and Ian La Frenais's Porridge. That show had a great gallery of characters and not a duff moment in any episode. That's it. Great characters trapped in a situation."
The I'm Sorry I Haven't A Clue panellist said that he rated BBC1 sitcom Miranda and the second series of Rev.
He added: "We will laugh again soon... It's straightforward stuff: character, character, character. You don't need jokes, you don't need funny lines. The humour will come because the secret to the truly funny sitcoms is simple - they are basically all about life."