Two lanes of traffic at lights

[w00hoo_kent]

I guess I was caring too much about what other cyclists were thinking while they undertake to the left. Of course, I know that's a bad move.

Never worry about what other cyclists think :-)

It's all about assessing your own safety. I described my 'optimum' method for getting through the junction I mentioned without too much sitting around. 8 times out of 10 I'll probably come along there and various factors will mean that I'm much happier just sitting with the cars, vans and lorries. Sometimes filtering makes sense. If you're going to filter do it from a position of knowledge. The important thing to remember is that car drivers will pay less attention to their left hand side than their right (especially if they normally get motorbikes filtering as well, which is the situation in London) and you always need to leave yourself a viable escape option. Sandwiched between two cars (or generally worse the car and the kerb) doesn't really count.