I go to London.

The LTLP was a bit worried about me entering the City of Fear, but I am brave and will not let the terrorists win by changing my way of life and stopping me making a journey I don't like to a place I don't like to meet people I don't like and discuss things I don't like.

Truth be told, I do have a nagging concern in the back of my mind. Society has always had odd standards and ethics about the way we kill people (dropping TNT on their houses is quite all right, but poisoning their water supply is a bit beyond the pale). Anyway, seeing the photos in the newspaper of those nail bombs, I can't help thinking that they look quite unsportingly and unpleasantly... pointy.

As has been terribly demonstrated in London once before, these devices are used only by the genuinely psychotic.

As my train draws out of Farringdon a man approaches and sits opposite. He has wet his pants. (i.e. literally, not as in 'he is very frightened about suicide bombers' but as in 'he is sitting opposite me in a pool of his own stale and foetid urine')

The gag reflex is fairly strong, but of course the not-wanting-to-appear-impolite reflex is superior. I do not know what the etiquette is when you are faced with a man who has wet his pants. One lady on the other side of the carriage subtly gets up and moves. I nonchalantly stare out of the window, which is not very interesting when you are under the ground, although there is some interesting cabling to study.

He looks shabby and a bit run-down, but not down-and-out. I have forgotten all about suicide bombers in my curiosity, although it would be nice now for him to go somewhere else, preferably well-ventilated. A ticket collector approaches. My urine soaked companion has a valid ticket. As the train emerges into the daylight at Blackfriars, he pulls out a mobile phone and makes a call.

Perhaps he works in the media and there was a big feature about tramp-chic in Guardian Weekend that I have missed. Or he has upset some people from Dynarod. Or he wet his pants in an accident some days ago and his wife has not yet got round to washing his trousers.

A crowd enters the train. As one, they turn and head in the opposite direction, some passing through the connecting door into the next carriage. Nobody wants to be near us.

At which point, I realise. He has cleverly wet his pants because he will be safer from terrorists that way. It seems rather drastic.

He alights at London Bridge. I rise and sit elsewhere.