Proposed video technology trial: Key questions and answers
The Football Association is keen to trial video technology in the FA Cup next season.
A two-year experiment has been proposed by the International Football Association Board (IFAB), the game's chief law-making body, and could be rolled out as early as August this year.
Here, Press Association Sport takes a closer look at how the technology would be used.
How will it work?
A video assistant referee (VAR) will watch the action simultaneously and be able to communicate with the referee by radio during the match.
What can be reviewed?
Any incident relating to a goal, red card, penalty or case of mistaken identity. Yellow cards, including second yellow cards, cannot be reviewed.
Who initiates a review - the referee or video assistant?
Both. If a referee is unsure he can ask the video assistant to review an incident. Equally, if the video assistant believes a mistake has been made, they can advise the referee to review it. The referee can immediately accept the video assistant's recommendation or consult the footage himself.
The referee can watch a replay as well?
Yes. If a referee wants to review an incident himself, there will be a monitor available on the side of the pitch.
Will the game always have to be stopped whenever there is a review?
No. If a mistake is immediately clear to the video assistant, they can tell the referee and he can act instantly. If the referee needs to stop the game he will make a signal - yet to be decided but likely similar to the one used in rugby denoting a screen - and then come to a decision.
Can players or managers ask for a review?
No. There will be no appeal system, as is used in cricket and tennis, open to players or managers.
Who has the final say?
The referee. His video assistant can offer advice but the referee's decision is always final.
What angles will he be able to look at?
The footage will use regular broadcast feeds so the referee and video assistant will be able to see the same replays as a viewer at home, no more, no less.
How far back can a referee go to review?
Only incidents occurring in the most recent phase with the ball in play can be reviewed. Once a restart has occurred, all the action before is effectively wiped.
Won't there be too many stop-starts?
It is something the test is looking to find out. Trials in Holland suggested corrections could be made in, on average, 12 seconds. Any time taken to review incidents will be added on as extra-time.
So what happens next?
IFAB have presented the experiment to a number of associations and leagues. They will analyse its effect on referees, players, coaches and fans at the end of a two-year period. If successful, video assistant referees could be officially introduced into football in either 2018 or 2019.