In front of me, a man in a black leather jacket was taking his time. Not for him the simplicity and ease of choosing a predesigned sandwich. No. He was going off-menu. Improvising a new and elaborate creation. He was a lunchtime maverick, operating outside the boundaries, like a law unto himself. I watched as he selected his ingredients, mixed and matched, chose the perfect bread and then the right sauce. He added a little cheese, I think, and certainly a smattering of jalapenos. He asked for some salt and pepper, and requested it not be toasted, and then he made the server take out some of the lettuce, because it was 'just too much'.

At first, I was annoyed at the man.

Who is this clown? I thought. Who does he think he is, laughing in the face of sandwich convention? Why does he not simply order a Sweet Onion Chicken Teriyaki sandwich like the rest of us?

But I maintained my dignified silence. Soon he would be finished, and I would finally be able to order my drab and soulless lunch.

'Ah, hang on,' I suddenly hear him say. 'That's not what I asked for - I asked for the six-incher. Not the whole sub. I told you that.'

There is a slight harrumph from the server, who mutters something about not being told to stop, and a sigh is passed down the queue as we realise our wait will be extended by a few more seconds. I look at my watch. And I think of my train. And I suddenly say, 'Look, I'll have the other half. I don't mind. I just want to get out of here.'

The man smiles at me, and says, 'Are you sure?', and I nod graciously but with eyes closed to indicate that this is an extraordinary gesture on my part. He leaves with his six-incher, and I watch him head into M&S, and then I pay for mine and hurry along the street towards the tube.

And it is there, on the high street, that I take my first bite.

'It was a taste sensation,' I tell Colin. 'Light without being frivolous. Substantial without being overbearing. It was a thing of such beauty that words cannot do it justice.'

'Who was he?' asks Colin. 'Who was this man?'

'Who knows?' I say. 'But oh, what taste he has! He probably drives a classic Jag, and drinks freshly brewed coffee on his Eames chair while his supermodel girlfriend naps on the Chesterfield! He probably has a cat named something classical, and a favourite red wine! I bet he uses moisturiser and summers in Italy!'

'Definitely!' said Colin, wide-eyed. 'If his Subway sandwich is anything to go by!'