If the lights flash amber you can go if its safe to do so (this is telling you that the lights are going to go green).If the lights solid amber, then you are being warned that it is going red and so you should stop. (from memory - can't be 100% sure that's right). But anyway, you say that you saw a pedestrian started to walk across the road but don't say anything about trying to avoid, brake, swerve etc to avoid collision. How far away were you when he started walking? was the light still green when you got to the lights (not when you saw them turn green 20 metres earlier)? the pedestrian was 3ft into crossing the road when the collision occurred so you should have spotted him before reaching him. It is not necessarily always the case that the driver is at fault, as clearly some pedestrians take no care for their own safety, but you are under a duty of care to pay proper care and attention and take evasive action if possible. Need more details about accident circs before can advise you properly. But there's no counterclaim to be made....what for and on what basis?