Not quite true, mdoo.
As a bus driver, aware that your passengers are not belted in and may be standing, you have to make a very rapid decision on how firmly to brake. On occasions the driver may accept an inevitable collision rather than slam on the anchors.
I don't believe there is anything in the highway code on this, and a decision on whether the driver was negligent would probably have to be tried in court.
It may be that a bus company would make a financial settlement out of court, but I think they would wriggle hard first. Do you have any witnesses, Libby?