London seems fairly quiet for techno outside of the squat party scene. Lost and Nuclear Free Zone are the only long-running techno club nights I can think of at the moment, although there's usually one or two each month as well.

There's tons of techno in the squat party scene though... probably half a dozen or more parties each weekend, the majority of which play techno in at least one room. Lots of rigs - Malfaiteurs, Manik, Stinky Pink, Tinkerbell, Tribe of Munt etc etc.