The VAR revolution in English football will gathered pace on Monday.

And while football fans have been warned not to expect the game to be perfect they have been assured it will improve.

Referees’ chief Mike Riley hopes the introduction of a video assistant referee – being used for the first time in a competitive match for the Brighton v Crystal Palace FA Cup tie – will go a long way to helping slash officials’ mistakes.

Riley said: “The biggest challenge is understanding that this isn’t about making the game 100 percent perfect.

“It is to address and reduce clear and obvious errors. We don’t want this to sanitise the game or for it to be stopping every two minutes while everyone stands around and gets frustrated.

“The select group of referees get 96 percent of decisions right, so four percent wrong.

“We don’t want errors in the game and if this improves it by two percent then the game has improved. That would be two percent fewer decisions for people to get agitated about.

“That is good for the game — as long as we don’t increase interference, because we want to the game to flow.”

VAR QUESTIONS AND ANSWERS

Which games will VAR technology be used for?

The first will be Monday’s FA Cup tie between Brighton and Crystal Palace. Then both legs of Chelsea and Arsenal’s EFL Cup semi-final, the first of which is on Wednesday. Also the EFL Cup final on February 25 and selected future FA Cup games.

What about the Manchester City and Bristol City EFL Cup semi?

Only Premier League grounds have the technology to get the footage back to the league’s TV HQ in Uxbridge. It would be inconsistent to use it in one of the legs and not the other at the Championship club’s ground.

How does the set-up in Uxbridge work?

The VAR — the fifth member of the refereeing team who will be in constant communication with the on-field referee — will be based there, along with an assistant VAR. Neil Swarbrick will be this week’s VAR, assisted by Peter Kirkup. Kirkup will ensure footage is still being monitored whenever Swarbrick is in touch with on-field referee. For games with 12 camera angles, there will also be one replay operator; for more than 12, there will be two replay operators.

What can they see?

They will have access to every camera angle, plus the four goal decision system cameras. Crucially, they won’t see what broadcasters show – replays etc – so will remain uninfluenced by anything external to what they see on those camera angles.

When does the VAR get involved?

This is key. Only when they spot a clear and obvious error. If they do, they need to communicate that to the referee. If they don’t, they stay out of it and let the referee’s decision stand.

Who decides when the VAR gets involved?

The VAR only. A referee can’t say, ‘I’m unsure, help me’ if they are in doubt. They have to make their decision first and if the VAR wants to get involved, they can.

How long does a VAR have to flag up an incident they have spotted?

The VAR has until the next time the game restarts to intervene. So if something like Ashley Young’s elbow on Dusan Tadic happens, the VAR might spot it, communicate that they are checking footage and if the ball goes out say, ‘Do not restart the game’ until they have dealt with it.

If the game has restarted, there is then nothing that can be done.

One exception is violent conduct, if it takes place during a stoppage in the game, officials are given two phases of play to come back to it as sometimes checking that can take a bit longer.

What incidents can a VAR intervene for?

Only four – goals, red cards, penalties and mistaken identity.

What EXACTLY within ‘goals’?

It takes, on average, 30-40 seconds to review incidents so there will be time here while the game is stopped. The VAR will look at all aspects leading up to a goal that might have been missed, including offside, any offence by the attacking team in the build-up and the ball going out of play prior to goal.

What about red cards?

The VAR will only intervene if he thinks the referee has missed a direct red card offence, not a yellow or second yellow. However, there are three instances when the VAR can advise a referee to issue a caution. 1) If, on reviewing a penalty it turns out there is simulation. 2) If, on reviewing an awarded goal, it turns out a player has deliberately handled the ball to score. 3) If, in dismissing a player, it is proved they have been provoked into retaliating, the player who initiated the incident could get booked.

What about penalties?

Should it have been awarded or not, inside or outside the box, was it a foul by the attacker? VAR can also get involved in double touch and encroachment that has an impact, for instance a rebound being scored or cleared by a player who encroached. A keeper moving off the line is left to the on-field official.

Mistaken identity?

This is simple. Think Arsenal’s Alex Oxlade-Chamberlain and Kieran Gibbs in 2014.

This would have been picked up and discipline transferred to the correct player. It can only be transferred within a team though, not from Team A to Team B.

How are incidents reviewed?

There are two types. The VAR can inform the referee there has been a factual error that does not require the referee to see the video, such as a goal being scored from an offside position. The second is the on-field review where the VAR advises the referee to re-watch footage on a pitch-side monitor and reconsider their decision. In both cases the referee will make a TV signal gesture before communicating the final decision. History shows there is one on-field review in every three games.

How long does this take?

On average from time the game is stopped to restarting it is taking about two-and-a-half minutes.

Can a referee overturn his decision based on a review?

Yes. The final decision rests with the on-field referee.

Does the referee have to change his decision if challenged?

No. If they review a decision but are comfortable with their original call they can stick with it.

Can managers or players appeal for an incident to be reviewed?

No.

What if they try to pressure referees into changing their decisions?

There is a two-stage punishment process for managers. If there is just genuine inquisitiveness, the first stage is a warning. But if they encroach on the three-metre marked area around the monitor and clearly try to influence the decision they are sent to the stands as second stage.

What about players and subs?

They are also not welcome within that three-metre area. Inquisitiveness is a warning. Any attempt to influence the decision is a yellow card.

What next?

A fairly big consultation exercise with the whole game on how best to implement VAR so by the time the summer comes around and the Premier League are deciding whether to use it next season there is a better understanding of how it will work.