In case there are any cyclists or wannabe cyclists out there, Haringey (and presumably Islington) offer heavily subsidised cycle lessons/training (you pay £5 for a 2-hour one-on-one lesson; normal cost is £65). The lessons cover all levels from total newbies to anyone who just wants a few pointers on how to survive on London roads etc. It's pretty good. I believe they'll even provide a bike if you don't have one.

http://www.haringey.gov.uk/cycle_with_confidence.pdf