In that moment, I wanted to be that man. A plan started to form in my head. I would hang around in Subway all day from now on, and when he eventually walked in and ordered his sandwich, I would start to constantly follow him round. I would follow him into out-of-the-way but achingly cool little cafes that I would never have found, or designer boutiques that I never knew existed, and I would buy exactly what he did. I would trail him from aisle to aisle in the supermarket, picking up pasta sauces I'd never tried because I'd always bought Dolmio, or cocoa beans from the Andes which I'd never tried because I'd always just bought a Twix. I would be this man's copycat, and he my guru. It would work. It had to. Because that sandwich was bloody incredible.

'Imagine the museums I'll go to!' I said to Colin. 'Imagine the people I'll meet! The things I'll see!'

'And you're sure this bloke won't mind you following him around all the time?'

'He'll never know! And if he does, I'm sure that we will become great friends. He will see in me a soulmate to mentor. We will be united by exquisite taste.'

'We should go to Subway,' said Colin, suddenly. 'Maybe you can re-create that sandwich!'

I laugh, and shake my head. Poor, simple Colin. If only life were that easy, I think. Alas, it is not.

For a few days, I think about the man in Subway and his incredible sandwich. And then, one day, a week or so later, I spot him again, striding down the street with a Starbucks panini in his hand.

And my heart stops.

He is wearing the worst trousers I have ever seen. Bright red slacks with stupid pockets. The sort of trousers you'd buy in M&S on a dull and grey Wednesday afternoon after you've just been all picky in Subway. I am shattered.

Later that week, I return to Subway.

I wait quietly, and then say, 'Chicken Teriyaki, please.'

THE DIVERSION

It is a glorious day, and I am sitting in a cab in mild traffic, somewhere in central London, when I look out of the window and see someone I know.

It's his day off, and he is enjoying a coffee in the midmorning sun, alone and relaxing with the paper, and he seems to be very content indeed.

The cab creeps forward, but only a few feet, and I decide to give him a ring to let him know I'm staring straight at him. He will be surprised and delighted, and we will do that thing that people do when they're on the phone and can see each other, where we make big exaggerated faces and wave a lot.