From 8 October in Aylesbury to 4 November in Ipswich, I will be embarking on a 20-date, stand-up comedy tour of the United Kingdom. These will be the first live dates I have done in this country for 10 years, so I have been forced to examine my old act with a cold eye, and even I have to admit that not all the old material, dazzling though it once seemed, is entirely suitable for recycling on this tour. I don't think the Kajagoogoo gag will work any more, and the great "Willie Whitelaw takes his Sinclair C5 to East Germany" routine doesn't have the topical, up-to-the-minute punch it once had. It seems that there is nothing else for it but to write some new material.

Rather than just sit down in a quiet room with a note pad and lots of coffee, I have been trawling through all the old videotapes of my TV appearances during the last decade in the unlikely hope of finding some golden nuggets of comedy that I don't remember doing, which I can incorporate in the new act. But watching all these television shows recorded off the air since 1985, I constantly find myself neglecting to watch my own appearances and instead am drawn to the fragments of long-forgotten commercials and news broadcasts that bracket the various shows that I was on.

What's truly incredible about watching the news, say, is that the big headline story of the night, some event that seemed to be of enormous importance at the time, has now been totally forgotten, certainly by me, and I'm sure by you, too. For example, who now remembers the time in 1986 when a herd of cows took over London's County Hall and declared themselves to be the provisional government of Britain? From the panelled council chamber, they issued more and more desperate calls for animals to rise up and overthrow mankind, until they were finally massacred by a squad of balaclavered SAS men. It was an enormous story at the time, but who recalls it now?

And on the advertising front, do you remember Wrigley's Bum Flavoured Gum? In 1987, there was a gigantic promotional campaign on TV for this product. The television ad's hilarious tag-line, "Chew My Bottom Arthur", was on everybody's lips and comedians flogged the catchphrase to death, though after eighteen- or nineteen-thousand repetitions the joke started to wear a bit thin and the product vanished from our shelves.

But what is clear, watching old news programmes, is just how hysterical and superficial the coverage is. Every story is treated as being of earth- shattering importance, all kinds of experts are called in to vapour on at length and then the next night it's all forgotten and a completely different story is given the same breathlessly excited treatment.

And the stories all have to be about bad things, because it's too difficult to get worked up and weighty about some happy-smiley news. As far as the media are concerned, good news is no news.

Watching these old news programmes reminds me that television news has become a branch of the entertainment business. I seem to recall that one evening in the Fifties, the BBC didn't bother to broadcast the television news at 9 o'clock because, in the words of the announcer, "nothing had happened that night". It's impossible to imagine that happening these days - some story, no matter how small, would be pumped full of steroids and updated across the screen as an earth-shattering crisis.

Of course, going through old tapes and becoming engrossed in the bits in between, I am indulging in the classic "writer-with-a-deadline" gambit of work-avoidance.

Everybody has found themselves indulging in displacement activity at some point in their lives. I remember going to give a friend a lift to the airport, as she was off to America for six months. When I got to her house it was in chaos and she hadn't even started packing but was in the back garden ferociously dead-heading the roses.

However, compared with writers, the rest of the human race are amateurs when it comes to avoiding the job in hand. Many in my profession will do anything to avoid confronting that blank page. Housework suddenly takes on a fascinating attraction. You realise you've got all the time in the world to help your neighbour replace the clutch on his tractor.

People often theorise about what mysterious people created the hundreds of giant carved stone heads that dot the Pacific atoll of Easter Island. The explanation is easy: they were all carved by a single comedy writer, who had a commission for a sitcom pilot for Channel 4 that he was supposed to complete over the weekend. The Egyptian Temple at Abu Simbel was built by some writers from Brookside, and the Grand Union Canal was dug by the writers of Dad's Army, David Croft and Jimmy Perry.