Apologies all, I seem to have given an answer rather than a hint.
In my defence, I had a very nasty fall this morning when I popped out to get some milk. I stepped on a large and shiny padlock, causing my foot to slide forward and the rest of me to fall back, cracking my head on the pavement in the process. Wapping is not exactly the most densely populated of areas and so I was lying there stunned for a good 5 minutes before some helpful young lady helped me back to my feet.
Ah well, but for a few scrapes and a bruised ego I appear to have escaped relatively unscathed:-)