Ian Blanchard, the Senior National Game Referee Manager, says that even one assault a season is too many and they have a comprehensive support system in place for any referee who has been attacked.

BBC: Rise in attacks on grassroots football referees

The leader of the Russian republic of Chechnya has apologised for using a stadium public address system to insult a football referee during a match.

BBC: Chechen leader Kadyrov sorry for stadium PA outburst

Like the Hawk-Eye system it uses a computer to send a signal to the referee's watch when a goal is scored.

CNN: Does football need technology?