My 25 hours of being funny for money

Shortly before midnight on 1 March, I surveyed the scene from the stage of the Pleasance Theatre in Islington, north London. I had been on that stage for 24 hours and 45 minutes consecutively, only escaping from it when I took the audience out into the forecourt at 6.30am to give them a glimpse of the sun rising.

Now, members of that audience – most of whom had also been here throughout the 25 hours – were in various states of disarray. Some were asleep or nearly so; others were notionally awake, but seemed to have little idea of what they were experiencing; some wore the strained cheer of hostages thinking it better to stay on their captor's good side; and a good number seemed absolutely normal and bright. On the stage itself was a woman in a tent, who had been there as long as I had; a man in a onesie whose sallow, red-eyed face had been custard-pied 24 times; a couple of people who had just played 407 consecutive rounds of Countdown; and a well-known comedian who was about to perform an obscene feat involving eggs and his genitals, in exchange for contributions totalling £2,500. We had just auctioned a piece of paper, salvaged by Krishnan Guru-Murthy from a bin, for £100. Strewn across the space in front of me were – among other things – party poppers, Babybel wrappers, and the remains of a lasagne I had attempted to eat in the 18th hour of my performance.

"Do something funny for money" has been Red Nose Day's rallying cry for some time, but not everyone takes those words to heart in quite this manner.

Admittedly, it wasn't the first time in my career I had done something as ill-advised as this, and in the past I didn't even have the excuse of charity. The "marathon show" accidentally became my trademark in the last decade, when what began as a whimsical stunt at the 2004 Edinburgh Fringe snowballed into a psychologically punishing annual tradition. I performed 33-hour and even 36-hour shows, showing scant regard for my wellbeing, that of my family, and of course of the audiences who stupidly continued to attend these monstrous exhibitions of attention-seeking. They were never exactly stand-up comedy shows: to interviewers who asked how I was planning to generate enough "material" to get through the hours, I would often merrily reply that I generally managed it without any jokes at all. It was half true. There were jokes, all right, but they all arose from the audience's growing complicity in a Sixties-style "happening". The show rapidly became, as it were, about itself, developing its own culture of in-jokes and references, until a newcomer walking in towards the end would get the impression they'd entered an entirely different country. Or a madhouse.

This was all very well, but after seven of these shows in Edinburgh and Melbourne, I felt I'd made my point: that point being that I was an idiot, prepared to sacrifice my voice and large portions of my sanity in a quest for what passes as love from people too tired to know better. In 2009, after a total of 189 hours on stage, I announced that I was leaving the arena of the medically unwise endurance show. Never again would I perform for so long that many spectators arrived with sleeping bags and food supplies; for so long that audience members could – as someone once did – go to France and still make it back in time for the climax.

But then came the request from Comic Relief to revive the day-long format for charity. Actually, slightly more than a day: 25 hours to mark their 25 years in existence. While ennobling what had always previously been a massive exercise in self-indulgence, the charity aspect introduced some new pressures. A live internet feed would mean the content would have to be at least partly comprehensible to the casual viewer. And, in order to entice people into donating, some of it would even have to be good. I'd never worried about that sort of thing before.

Luckily, I wasn't alone. A couple of appeals via Twitter and my blog led to some astounding suggestions for 25-hour challenges which would run alongside mine. One man, Oliver Fisher, watched the execrable film Beverly Hills Chihuahua on a loop, chalking up 14 viewings; even by the end of the second, he was visibly weakening. There was a 25-hour piggyback and a 25-hour hug (the latter ratified as a Guinness World Record). There were houses made out of cake, there were day-long baths, 25-hour dating marathons; there was busking, knitting, and that custard-pie-enduring feat. Tiernan Douieb raised more than £1,500 by taking a pie in the eyes to mark the turn of each hour, while also trying to learn the piano from scratch in the allotted time. One of the pies was administered by a pair of professional clowns, who then dumped him in a bath of custard for good measure. Normally this would be an odd moment in a show, but at the 14-hour mark of this one, the audience barely turned a hair.

With all this activity, the Pleasance by the end had an atmosphere somewhere between a correctional facility, a primary school, a circus tent and – though less obviously – a comedy venue. I, as usual on these occasions, went through an unpredictable gradient of emotions. There was relief that things were somehow working out, concern for my shredding voice, a kind of benevolent capitalist fervour at the sight of the Comic Relief tally skyrocketing, and from time to time – as I admitted out loud when Jennifer Saunders was in the process of bidding £1,000 for Emma Kennedy to urinate on stage – absolute confusion as to the question: '"How did I cause these things to happen?" But at the bottom of it all was a woozy pride. As we were reminded by a visiting Richard Curtis – one of the more dignified figures to stand on the increasingly squalid stage – Simon Amstell, David Schneider, Janet Ellis, Adam Hills, Josh Widdicombe and Jonathan Ross were among the many others who also called in – even 50p can help to provide essential inoculations in the areas of Africa where Comic Relief works; £10 or £20 can provide food, counselling and support for desperate people in that continent and in the UK. With that in mind, our overall total – £58,334 at the last count – feels like something to be happy with, even if having stood on stage for 25 hours is less an achievement than a sort of comedic cry for help.

Previous shows proved that I could perform for a very long time. This one proved that many other people can, too, and that the sum total of their seemingly pointless efforts can be a stupid but valuable one.

Highlights from Mark Watson's 25-hour show will be broadcast on Comic Relief on Friday at 7pm on BBC1. You can still sponsor Mark Watson at rednoseday.com/sponsormark. If he has inspired you to do your own fundraising for Red Nose Day, go to rednoseday.com/fundraise to find out more