The only way to get to grips with London is to stand there and wonder: wonder why most nights when I leave the tube station I see a solitary unicyclist weaving through traffic with a street hockey stick balanced on one shoulder; why a sturdy looking middle aged woman in pearls and wearing a gilet would be walking a lamb on a lead through some of Kensington's most chi-chi streets; why every time I go to Shepherds Bush, I see a man who looks like GB Shaw; or why Chiswick has a disco-dancing street cleaner.

Tube pass, gritted teeth, sense of wonder, that's really it, everything you need to get to grips with London. Toolkit for London I suppose.

Still, not every question remains unanswered. Closure does happen. There's a solution to the puzzle of the keys on the bus shelter roof for example. May not be the answer, I admit; but it's plausible, and I like it.

Those keys were the fall-out from a stag-night. Groom de-bagged, ball and chain locked round an ankle, then house keys, car keys, and the keys to the leg-irons flung on top of the bus shelter. One hand cupped round his groin, the other vainly clutching a ball and chain, tottering along the High Street. I can see this. I actually can.

I have to thank an anonymous poster for this solution. It's perfect.