I may regret joining in…
but I’m not very sure there was contact between the Jag and the bike. It looks to me (not there, don’t know, etc) that the Jag was further away from the bike after the fall than would have been the case had there been a bump. Otherwise, he’d have hit the bus too?
Might I also be so bold as to postulate the that Jag driver really was an officer of the law? Despite the ongoing discussion I got the impression of some room between car and bike. That doesn’t explain why the car drove away, unless it was to get off the main road so the driver could walk back to assist. I wonder what the next few minutes of film showed, or indeed the cameras that the bus driver mentioned.
I don’t know the junction, but got the impression that the choice of position by the cyclist could have been better – he said at the start that the driver was ignoring him, but chose to join the line of traffic there anyway. As others have said, the whole thing could have been so easily avoided.
My crystal ball/blatant construction says he was riding fixed on a road bike and caught the front mudguard with his foot.