Football is changing at a rapid rate in the modern age as VAR, expanded international tournaments, revamped UEFA competitions and now blue cards affect the beautiful game.

Referees have clamped down on dissent in the 2023/24 season, especially in the Premier League, and lawmakers at the International Football Association Board (IFAB) have now granted permission for the use of sin-bins in elite-level football.

The introduction of blue cards is the latest way in which football looks set to change, though it is not a brand new concept around the sporting world.

Here, we’ll aim to explain everything about blue cards and sin-bins in football, from timelines to examples in other sports.

A blue card is given for dissent and cynical fouls and results in a player spending ten minutes off the pitch in the ‘sin-bin’ while their team continues with an on-field disadvantage.

Referees have clamped down on player outbursts this season, with Diogo Dalot’s red card for Manchester United away at Liverpool a prime example. As for cynical fouls, dragging a player down to stop a counter-attack will result in a more serious blue card rather than a yellow.

In an IFAB meeting, one example of a cynical foul used was Giorgio Chiellini’s shirt pull on Bukayo Saka in the Euro 2020 final at Wembley. The Italian defender was shown a yellow card, but under the new rules, the referee would have been expected to give a blue card.

This measure has been introduced by The International Football Association Board (IFAB), who are announcing trials where referees will have the power to sin-bin players at the elite level.

IFAB is set to give the go-ahead for extended sin-bin trials in senior levels of the game at its annual meeting in March.

There is no concrete timeframe for when blue cards will be seen in the Premier League or top international tournaments, but with the annual meeting not until March, it is unlikely to be this season.

There has been a real push from authorities in recent years to crack down on dissent towards referees and officials. Attitudes towards officials are a problem at every level of the sport and the blue card would theoretically give referees something else to battle it with, which in turn acts as a deterrent.

Mark Bullingham, chief executive of the FA, said: “When we were looking at sin-bins – protocol clearly has to be developed – the areas we were looking at were dissent, where it’s worked very, very well in the grassroots game in England.

“The starting point was looking at player behaviour and dissent – we’re then looking at whether we should extend it into other areas, such as tactical fouls, as well.”

There have been trials of blue cards in both amateur and youth football in England and Wales. Those trials led to IFAB agreeing in November 2023 for further implementation at higher levels.

FIFA has not reacted well to the idea of blue cards, calling it “premature” and saying “any trials, if implemented, should be limited to testing in a responsible manner at lower levels”.

The Times have previously reported that the FA is considering trialling sin-bins in the FA Cup and Women’s FA Cup in the 2024/25 season. They will not be used at the 2024 European Championship or the 2024/25 Champions League.

UEFA president Aleksander Ceferin said in January he is opposed to them, stating: “It’s not football anymore.”

Sin-bins, officially known as Temporary Dismissals, have been used in grassroots football in the United Kingdom since the 2019/20 season.

The most widely known example of sports using the sin-bin are rugby league and rugby union. If a player is shown a yellow card in rugby, they spend ten minutes sat on the sidelines. Two yellow cards also result in a red card.

This shows how football is going down a slightly different route, with three colours of card available to a referee rather than two.

There is a sin-bin system in ice hockey, known as the Penalty Box. Field hockey, lacrosse, handball, water polo and other minor sports have a version of a sin-bin.

This is where things may get a little complicated for the viewer, as there is a bit more to remember than just which players are on a yellow card.

If a player is shown two blue cards in one game, the second will result in their dismissal for the rest of the match. A player can also be sent off if they receive a blue card and then a yellow card later in the game after their reintroduction.

The punishment will be ten minutes long. Getting a blue card in the final few minutes of a match will mean that player’s day is up.

According to BBC Sport, Man Utd’s Bruno Fernandes is the player who would have received the most blue cards during the 2023/24 season, as of 9 February 2024. He is level at the top with Chelsea’s Nicolas Jackson and Fulham’s Andreas Pereira, who all would have received four blue cards.

Matheus Cunha, Diogo Dalot, Enzo Fernandez, Gabriel Jesus, Sean Longstaff, Neto and Lucas Paqueta would all have received three blues during the campaign so far.

Opta have recorded yellow card statistics since the 2008/09 season, including bookings specifically for dissent. Man Utd legend Wayne Rooney is the undisputed champion with 15 yellow cards for dissent, having last played in the Premier League in 2018.