How are VAR lines drawn in soccer? How is the forward ball played determined? Is the technology reliable enough? Answers to major offside queries explained following Man United’s fortunate moment in Coventry.

It’s fair to say that a number of football fans were left bemused by VAR’s decision to rule out Victor Torp’s late winner for Coventry against Man United on Sunday.

VAR ruled that Haji Wright was offside by a fraction after he assisted Torp in the 121st minute at Wembley, with Coventry thinking they had finished a generational comeback to win 4-3.

Many argued that it ‘ruined one of the greatest FA Cup moments ever’, as the Red Devils eventually went on to win the semi-final after a 4-2 penalty shoot-out victory.

So, here, Mail Sport answers all the burning questions about VAR’s offside process. 

WHO IS IN THE VAR ROOM?

VAR may stand for ‘Video Assistant Referee’ but there are actually three officials who work together to help reach an on-field decision. 

Firstly, the lead official judges the reviews, while the assistant continues to watch the match as the his colleague makes a decision.

Meanwhile, the third official is the Hawk-Eye operative and is tasked with controlling the VAR technology. They remain independent of the decision-making process.

HOW ARE THE LINES DRAWN?

As per the official Premier League website, VAR uses two-dimensional lines – one placed on the attacker and one on the defender – to make offside decisions. 

A crosshair is used to identify the exact position of the offside line, so that the relevant body part can be accurately identified by the VAR. 

VAR lines are drawn on the leading part of the defender and the leading part of the attacker with which they can score. 

The decision also has a ‘tolerance’ level in favour of the attacker if the lines touch, which gives the forward the benefit of the doubt. 

In that case, a green line would be shown, but the lines were not touching in the case of Wright and Wan-Bissaka, meaning there was no doubt.

So fine were the margins that Coventry boss Mark Robins joked Wright would have been considered onside had he cut his toenails. 

CAMERAS AND FRAME RATE

In the Premier League, VAR makes use of five in-stadium cameras to aid in their Hawk-Eye technology. 

There is one main wide camera, two 18-yard box cameras and two goalline cameras. 

Hawk-Eye is also able to use any broadcast camera to identify the point of contact with the ball by the attacker.

The officials then go frame-by-frame to identify the first point of contact of the passing act, not the point of release. 

The Hawk-eye operative then selects three frames for the VAR, who will choose the one that represents that first point.

Broadcast cameras only operate with 50 frames per second, so the point of contact with the ball is one of those frames inside the 50 per second.

However, this aspect of VAR is one that has been particularly criticised, with doubters claiming the technology is not good enough to make these tight calls. 

If the correct frame is not actually be available, the VAR must select the first frame where the ball has definitely been touched.

WHY ARE SOME VAR PICTURES DECEIVING?

Often, still-images of VAR can look deceiving for viewers at home.

Unless one of the available cameras is directly in line with the final defender, the player’s body position may look further forward or back compared to reality. 

According to the Premier League website, if the broadcast camera is not perfectly horizontal – the vertical line can appear to lean to one side. 

This perhaps explains why many felt aggrieved by Wright’s ruled out assist, which – from certain angles – appeared to be incorrectly drawn.

WHAT IS BEING DONE? 

Well, English football will embrace semi-automated offside technology from next season, with the system expected to cut VAR delays by 30 seconds.

Premier League clubs voted unanimously yesterday to introduce the new system, which has been deployed successfully in the World Cup, Champions League and other major domestic leagues.

But there will be a further delay to its arrival, which is not scheduled until after ‘one of the autumn international breaks’ next season. 

Twelve cameras will be installed under the stadium roof to track 29 data points on the players, allowing a much more accurate measure of when a pass is played. If a player is offside, the system sends an alert to the VAR official, who decides if they are interfering with play.