When is it OK to drink alone?

Drinking alone is generally bad and depressing. There's nothing right about quaffing budget cider under a bridge or guzzling Smirnoff Ice on a bench next to a busy A road, is there?

But there are exceptions. Sipping scotch in front of an open fire is okay, as long as there's opera playing in the background. And it goes without saying that solo boozing on an aeroplane is acceptable at any time of day (as long as you're not at the controls). But does train travel fall under the same amnesty?

Last week, I boarded the last train home from Manchester and found myself without a seat. Facing a two-and-half-hour journey standing up between carriages, the row of frosty-looking Heinekens in the buffet car started to look curiously tempting. But could I do it? Did I really want to be that bloke with the can of lager on the last train home? Then again, who would ever know?

Boarding a train is a bit like boarding the Tardis - the space/time continuum is temporarily suspended and normal rules don't apply. The Heinekens, the jumbo bag of salted cashews you have for your tea, the bit of wee you accidentally get on your iPod whilst wobbling around in the toilet compartment - it's all erased from the record the moment you step off that train.

Only it isn't. You're still drunk, you're still alone and a little part of your soul has been blackened with shame forever. Back at Euston I bought a Cornish pasty from a kiosk and jumped into an overpriced taxi home - with only my overwhelming sense of self-disgust for company. ·