The mission: With a nylon wig, a new cleavage and stiletto heels, will even her father recognise Maggie O'Farrell?

Accepting a mission to spend a day in

disguise, I had been envisaging stalking about in a Zorro mask. But my theatrical-costumier friend tells me that the art of disguise isn't necessarily about covering yourself up. "Think of your most distinctive features," he tells me, "and how most people recognise you, and then subvert them." That means my hair, I decide, my flat-chestedness, my huge nose and the fact that I never wear proper women's clothes. He produces from his bag of tricks an Uma- Thurman-in-Pulp-Fiction wig, an Ultrabra, shoes with heels like knives, and a ridiculous dress that will make me look like I'm about to sing "Happy Birthday Mr President". What about my nose, I ask. We can't do anything about that, he replies.

I have reddish ringlets that on a bad day give me a remarkable resemblance to the mad woman in Angel at my Table. The wig is a shock; all my life I've wondered what it was like to have hair that grew straight and sensibly from your head, and now I have several inches of best-quality nylon hanging either side of my face.

I totter out into the street, disorientated and missing my trainers. I pass a group of people who stare at me. I realise it's 11am and I'm dressed like a high-class prostitute. The Ultrabra is very odd: every time I look down I see these breasts that don't appear to belong to me, perched on top of the dress.

I have arranged to meet two friends for lunch. When I stagger to the cafe table next to them, they are deep in conversation. One of them glances at me briefly, then looks away. They are talking about a friend of ours who is trying to decide between two men.

"Excuse me," I lean over and say in an accent that veers giddily from Bangor to Bangalore, "do you have the time?" I have the disconcerting experience of one of my firmly platonic male friends staring at my cleavage before he displays his watch for me to look at. "Are you from around here?" I continue. They exchange uneasy glances "Um ... " mumbles my usually articulate and loquacious friend, "kind of." The other one looks out of the window. "I wonder where Maggie is," he says. I can't keep it up any more. My laughter explodes from me in an unattractive swine-like snort. "It's me," I bellow. The effect is impressive; they both leap to their feet, making horrified gargling noises. "We thought you were a mad tourist trying to chat us up."

Conversation from this point on is a dead loss: you'd think after about 10 minutes the surprise would wear off and we could carry on as normal. But two hours later, they are still staring at me as if I have a parrot on my shoulder. "This is better than TV," they keep saying.

My father is in London for one night only - and we are due to have dinner, during which he will attempt to force me into joining a pension scheme. When I approach the restaurant he is waiting outside on the pavement, peering irritatedly at his watch - I am, after all, an unreasonable 45 seconds late. Will my own father recognise me? "Do you have a light?" I ask him, safe in the knowledge that be is a fascistic anti-smoker and, therefore, there is no danger of my nylon hair being accidentally ignited.

"Pardon? No." he says without looking at me twice. I withdraw to the loos to reinstate my true identity before we begin talking about pensions