Is the silver car the old Vectra on the hard should afterwards?
If so I think there’s a strong smell of crash for cash here. If it was a silly revenge brake-checking then I think they would be considered the one at fault.
A few points:
Post dashcam it is not any longer the case that anyone who goes into the back of the vehicle is automatically at fault (if indeed that statement has ever been wholly true). If dashcam shows brake checking insurers have not paid out. For a long time, prior to dashcams, a lot of drivers pulling out late from junctions have got away from it providing they have fully turned into the carriageway. We’ve all seen them rapidly pull out then seemly give up on accelerating once they’re in the carriageway thinking it’s then for the vehicle behind to brake.
Secondly, not sure about separation distances I believe they are based on the vehicle in front emergency braking I don’t think they allow for the massively more rapid deceleration of the vehicle in front hitting a near stationary object. In some situations an observant driver behind at a safe distance can still be unfairly compromised by the distracted driver with poor observation and separation distance in front of them.