As England's players decided whether or not to leave the field on Monday night, there was much talk of UEFA's three-step protocol against discrimination. First, there would be a public announcement ordering the end of the offensive chanting and if that didn't work, the players would leave the pitch temporarily. If there was still no improvement, the game would be abandoned.

As it turned out, events hovered between the first and second steps. When the announcement didn't quell the abuse, England's players huddled on the pitch while the referee methodically consulted with UEFA officials. After a delay of around five minutes, the match continued. 

However, there is another three-step UEFA system which Bulgaria is now likely to be moved along. Written into UEFA's rules is a trio of punishments for any club or country whose supporters insult "the human dignity of a person or group of persons on whatever grounds, including skin colour, race, religion or ethnic origin." 

Step One: Partial ground closure

Bulgaria was already on the first punishment step: "a minimum of a partial stadium closure." After Bulgaria fans were found guilty of racist behavior during Euro 2020 qualifiers against Kosovo and the Czech Republic, UEFA mandated that 5,000 of the 46,340 seats at the Vasil Levski stadium in Sofia be blocked off for the game with England and 3,000 against the Czech Republic next month.

Bulgaria is far from the first team to be punished in this way. Poland, Greece and Croatia have had similar partial closures, as have clubs in UEFA competitions like the Champions League - including Steaua Bucharest, Debrecen, Maribor, FC Chikhura Sachkhere, Spartak Moscow, Zenit St Petersburg and Atletico Madrid.

Step Two: Behind closed doors and a fine

UEFA's rules for repeat offenders are straightforward: "a second offence is punished with one match played behind closed doors and a fine of €50,000." Among the recipients of this punishment at club level are Dynamo Kiev, Lyon, Slovan Bratislava, Partizan Belgrade and Red Star Belgrade, along with countries Romania, Montenegro and Croatia.

Even here, though, there is confusion and claims of rule-bending. Slovan Bratislava was punished after fans made racist chants and displayed a racist banner against Greek side PAOK. They will play a Europa League game against Wolves later this month "behind closed doors" - but roughly 5,000 fans will attend anyway, because children under the age of 14 are permitted if accompanied by an adult.

Step Three: Anything up to disqualification

After the clarity of the second step is the complexity of the third step. Here, UEFA has given itself a lot of leeway: "any subsequent offence is punished with more than one match behind closed doors, a stadium closure, the forfeiting of a match, the deduction of points and/or disqualification from the competition."

This obviously covers a lot of ground and allows UEFA to respond according to what it perceives to be the severity of the offence, including moving beyond fines into sporting sanctions such as point deductions. It is worth noting, however, that only once has UEFA gone that far once. 

In July 2015, Croatia - having within the previous six months received a partial stadium closure and then a one-match stadium ban - was punished again after a swastika was chemically burnt onto the pitch before a Euro 2016 qualifier. The country was docked one point, and remained top of its qualifying group.