Referees committee chairman Pierluigi Collina has confirmed FIFA cracked down on holding by defenders at set-pieces after a series of early incidents at Russia 2018.

Speaking to reporters at a briefing on video assistant referees (VAR) in Moscow on Friday, Collina was asked why England’s Harry Kane and Serbia’s Aleksandar Mitrovic were not given penalties for being held during games against Tunisia and Switzerland, respectively.

Collina explained he would not comment on specific incidents, but said: “You might have appreciated there were some incidents that suddenly disappeared or started to be punished. It’s impossible to be right from the start but because we noticed, we intervened and we fine-tuned. Things have changed during the tournament.”

In general, Collina and his committee colleagues said they believe VAR has been a huge success.

Having reviewed the first 48 games, Collina said there have been 335 incidents checked – nearly seven per game – with 14 on-field reviews made by referees and three reviews made by the VAR team on “factual decisions”, such as off-sides.

Of these incidents, referees called 95 per cent of them correctly without VAR but replays improved this to 99.3 per cent by correcting 14 of them: six penalties awarded after an on-field review, a penalty given by the VAR because it was shown the foul occurred in the box, two penalties cancelled after on-field reviews, two potential red cards confirmed as yellows, two goals awarded after potential off-sides and a mistaken identity for a booking.

“We have always said VAR doesn’t mean perfection – there could still be the wrong interpretation or a mistake – but I think you would agree 99.3 per cent is very close to perfection,” said Collina.

To illustrate why FIFA is so pleased with VAR’s introduction, the 58-year-old Italian showed reporters clips of four contentious moments, complete with footage from the VAR control room and the audio link between referee and VAR.

Asked if FIFA would consider letting broadcasters use this audio, Collina said: “Before running you have to learn to walk. I don’t know what’s possible in the future but I think it’s a bit early for that now.

“I agree it would be interesting, though, and would perhaps make decisions better accepted by the football community.”

Zvonimir Boban, the ex-AC Milan and Croatia star who is now FIFA’s deputy general secretary, added: “That would maybe be possible in a domestic league but would be hard at a World Cup. Which language would we use?”

As well as asking referees to look more closely at wrestling in the box, Collina revealed that officials were told they could ask for more on-field reviews than initially advised.

“We were aware VAR could interrupt the flow of play and time could be lost, so we wanted as few interventions as possible,” he said.

“But we noticed there were a few complaints – understandable complaints – about maybe doing more on-field reviews, so we thought it would be a good idea to do that so the decisions were better accepted on the field.”

As an example of this, Collina cited South Korea’s first goal against Germany. It was initially ruled out for offside but this was reversed when VAR established Toni Kroos had played the ball.

Senegal's Sadio Mane and Colombia's Davinson Sanchez
Colombia defender Davinson Sanchez’s tackle on Senegal’s Sadio Mane was initially given as a penalty but VAR spotted that it was actually a perfect tackle (Efrem Lukatsky/AP)

In terms of any wider impact VAR is having, Collina suggested it was probably too early to tell.

There were just under 27 fouls and about three-and-a-half cautions per game, which is consistent with the major leagues, but there has been a big increase in the number of penalties: 24 already here, compared to 10 at this stage in Brazil and South Africa. Of the 14 additional penalties in Russia, seven have come as a result of VAR.

FIFA’s big VAR-related fear was clearly that it would cause delays but the ball has been in play for an average of nearly 57 minutes at Russia 2018, up from 55 minutes in Brazil, and VAR reviews have taken an average of only 80 seconds.