'This car,' I say, trying to give the sentence an air of finality, 'makes me look like a grown-up. Those youths may behave a little better knowing I am nearby, and were that man a criminal of some kind, he is now doubtless reconsidering his ways.'

'He is now doubtless considering your pimp wheels,' says Colin.

'You're the one going to a party down a street with a massage parlour on the end,' I say, and he gets out.

I have agreed to collect Colin in one hour - long enough for me to run an errand nearby and for him to pick up some money he's owed without it looking like that was the only reason he went to the party.

I turn the car around and make my way back through King's Cross, instantly feeling calm again. A Phil Collins track comes on the radio and I drive towards Holborn, where I'm dropping off a CD for a friend.

Parked up, I climb out of the car and try to walk away without looking at its wheels.

I can't. And I realise, with some horror, that yes, they do look slightly too big for the car. My heart sinks. Maybe I do look like a pimp, driving around London, delivering packages and collecting people who are owed money.

But no. This is ridiculous. Why should pimps have the last word on wheel size? If they were that bothered, they'd drive tractors.

I drop off the CD, and try and shake off the feeling that Colin has ruined my car.

On the way back, I attempt to think of ways to get revenge. I could say his shoes make him look like a baker. Or that he's got a jockey's hairdo. But I can't quite put my finger on the thing that'll rile him most.

As I'm thinking, I somehow miss my turning. I drive back around to look for it again, but to no avail.

Where's that street gone? I pull up and give Colin a call, but it goes straight to answerphone.

Ten minutes later, and I still can't find that street. I know it's round here somewhere, but it's nowhere. I've lost Colin. And right now, he's probably outside, waiting for me, near youths kicking beer cans and that nervous man, who was probably nervous because he was a mugger! Oh God! Colin's going to be mugged by a nervous mugger! I have to find him!

Panicked, I pull up, and roll my window down.

'Excuse me!' I yell to a passer-by, who eyes me so suspiciously that I want to shout, 'I am not involved in prostitution!'