For the record, I wasn't stoned on Question Time. I just felt I wasn't the real me

The notion that "strong" people can behave and look exactly the same whichever environment they are in is very noble rubbish. Those of us who work mostly from home live in dread of the videophone and the webcam because we like having secret alter egos. Most days are spent in pleasant slovenliness: sticky-up hair, dirty tracksuit bottoms and spotty skin denied the luxury of heavy make-up. Once or twice a week, we throw off our sad rags and pull on our glad rags. As one colleague, who caught me shopping in my "real" clothes last week, kindly pointed out: "God, you don't 'alf scrub up well."

Which reminds me of poor Chloe. At college one hot, summer afternoon, Chloe forgot where she was. We were stuck together in a history of theatre lesson. Everyone was struggling to stay awake, when the bubbly blonde shifted in her seat, lifted one buttock as high as she could and let loose a fart of such force and magnitude that the rest of us flew from our chairs in surprise. As tears welled up in her eyes, she came out with the most honest apology for unexpected behaviour I've ever heard: "Sorry," she wailed, "I thought I was at home."

On my first appearance on Question Time recently, I was due to be smart/glam and smart/intelligent by seven in the evening, in Wolverhampton. The trouble was that, three hours earlier, I had been pottering around my family's new "holiday home" in Wales - a wood and canvas structure called a "yurt", with plastic sheeting for flooring and three musty mattresses for bedding. My daughter had spent the afternoon gleefully cramming pebbles into her mouth and screeching with joy as she discovered chickens, bonfire ash and muddy puddles.

Alli, the fiftysomething, muscular handyman of the commune, who never stops working, had built the yurt for us single-handedly. At first, Alexandra was timid around him. True, his craggy face, snaggle-toothed grin and punk hair can take a bit of getting used to. But soon she, like everyone else, loved being in his company. The others on the site were busy building a new drama space and adding showers to the existing two farmhouses. I wandered through the yurts, caravans and trees, savouring the aroma of farm air and marijuana.

Two hours later, in the large hall at the back of a Wolverhampton leisure centre, I listened meekly as Julian Fellowes, Tim Razzall, Roy Hattersley and John Redwood chatted about topics ranging from the Oscars to the business disaster of digital TV.

Each time I tried to join the conversation, my brain failed me. Each thought tailed off into nothingness. And just for the record, no, I wasn't stoned. I never smoke dope before going on political panel shows - although I have often thought that passing a joint around before going on air would liven some people up a bit and make brilliant TV.

I looked at my nails and they were broken and dirty. I looked at what should have been sharply pressed black suit trousers and saw instead creased jeans splashed with mud. The make-up lady tightly mentioned my "not very bouncy hair". I knew she meant it was greasy and stank of woodsmoke. I prayed I was just having a nightmare - that really I was in full "Lauren Booth" costume. But there I was, Jerry Lewis in The Nutty Professor, two personalities waging embarrassing war on each other in public.

After the show, I rushed back to Wales to party with my mates: a girl rapper who records with Chumbawamba, a single mum living in a mobile home and a drama therapist. Walking into the upstairs living room of the eco-house, I expected to hear loud chat and laughter. Instead I heard David Dimbleby say "and this week on the panel I am joined by . . ."

I now know how famous politicians feel when they are imitated. For the next half-hour, I watched someone doing a really bad impersonation of Lauren Booth on Question Time.