A "fairer World Cup", better player behaviour and a reduction in the "mobbing" of officials.

The introduction of video assistant referees was one of the major issues heading into this World Cup and, as expected, it has been a near constant talking point during the first round of games.

Four penalties have been given using VAR, while England and Brazil both had cause to be unhappy with the system.

Like it or not, it is certainly having an impact - 10 penalties have been awarded in 17 matches. The World Cup record is 18 for an entire tournament.

Former Premier League referee Mark Halsey told BBC Radio 5 live the failure of VAR to give spot-kicks to England for fouls on Harry Kane against Tunisia showed the system is "inconsistent" and "should not be in this tournament".

But Fifa says it is "extremely satisfied with the level of refereeing to date and the successful implementation of the VAR system".

And David Elleray, technical director of the International Football Association Board - the body which oversees the laws of the game, told BBC Sport its overall impact has been "very positive".

"There have only been five reviews in the first 17 matches, which conforms to the global average of one in every three games," said Elleray, who helps to train referees in the use of VAR.