Taken from the Tfl website
Top tips for cyclists:
Take a safe start position at lights
Wait in front of other vehicles when you’re at traffic lights – the blue painted box with a white cycle symbol shows you where.
Arrgh. I cannot get there, a taxi is blocking my way. Should I go around on the right-hand side? I’ll try that. Arrgh. The lights have changed! Now I’m stuck in the middle of lanes of traffic. What to do?
Large vehicles at lights
Get well in front of large vehicles such as lorries and buses and do not wait on their left. Make eye contact with the driver so they know you’re there. If you can’t get in front safely, wait behind the vehicle.
Sound advice, I’ll just sit here sucking in diesel fumes until I pass out. Lorries should be banned in rush hour.
Never undertake a large vehicle at a junction
Avoid cycling on the left or near the front of large vehicles especially near or at a junction where the vehicle may turn left – the driver can’t see you. Take a cycle training lesson to learn how to be safe around large vehicles.
I’m new to this cycling lark. I wonder why the blue lane leads me down the left side of the lorry when I have been told it is dangerous to do so? Maybe a segregated lane at junctions would have been a good idea. No, that’s far to radical. Silly me.