I went to the transport research lab in London and did my advanced driving, they told me that after the light turns back to red, there is a 1 second delay, after which time the camera is active. Get confirmation though.
It's situation dependent also. The red light in the UK means 'STOP'. The amber light in the UK means 'Stop if safe to do so'. If you are approaching the lights and they are amber, you brake if you can. If you drive on hoping to beat the red, you are violating the law.
Yeah, to be fair, even at the proper speed, unless you are right on top of the lights, it should be safe to stop. The only reason to go through is if you were travelling too fast and it isn't safe to stop, in which case it's six of one, half a dozen of the other.