Masters snooker: Ali Carter and Shaun Murphy through to semi-finals

At 4-3 up, Carter was adjudged to have fouled when failing to make contact with the yellow, only to insist that he had in fact touched it, which in turn resulted in the referee reversing her decision.

Television replays appeared to confirm that there was in fact no contact, begging two questions: why did Carter insist that there had been, and regardless of that, why did the referee take his word for it?