Amongst the commuters this evening on the westbound District line platform at Monument Station was an onion.

A very patient onion, barely moving. Simply waiting like the rest of us.

Utterly absorbed, serene almost - imagine a small Buddha - and, like all commuters, scrupulously protective of his personal space.

I doubt if anyone else apart from me actually saw him - and he was there, believe me. It's one of the unwritten laws of commuting to never acknowledge there are other commuters. They're there, but not there, whether it's an onion or not standing alongside.

Crowds are like waves on a tube station platform: they break, they clear, and then gradually reform. People swarm off trains, swarm on to others. Tonight amidst it all was this fist-sized onion, resolutely in the same place, oblivious of the melee of legs and umbrellas rushing past.

I finally boarded the train I needed, so I can't say with any authority what happened to this indomitable Onion in the end; maybe he did roll on to a westbound train at some point, perhaps he got picked up, could be he just got fed up, turned round and however onions do it left the station. We'll never know.

Even how he got there is a mystery. Hurrying to board the Richmond train, someone bumps or trips, and out pops an onion from a shopping bag?

If it had fallen from a bag, should I have picked it up and chased after a progressively accelerating train, like a love sick swain desperate to press a favour in to the hand of his adored? Could there ever be a brief encounter at at tube station with an onion as a go-between?

Wanderlust, maybe, or a cri de couer ? "That's it...no more green dump bin... Tesco is too small for me... too humdrum... I need space...wide open space...I'm heading for Wholefoods...be a real onion...make something of myself...