England’s Euro 2020 group matches at Wembley will have 22,500 fans, the Football Association has guaranteed Uefa, with the hope this figure will double to 45,000 for the semi-finals and final. The numbers – which represent 25% and 50% of Wembley’s capacity – were discussed at a meeting on Thursday of the 12 host Euro 2020 cities. Fans will be expected to have lateral flow tests, or to show proof of a vaccination, to attend. It is also understood that anyone with tickets for England games will have to enter a ballot – with those not successful being given a refund. About 3,600 tickets will be reserved for Scotland fans for the England v Scotland group match on 18 June. Uefa also explored the possibility of granting more time to Dublin and Bilbao to guarantee spectators in grounds for Euro 2020, with a decision over whether to move any games unlikely to be taken for at least another 10 days. Meanwhile 10 of Britain’s leading sports bodies – including the Premier League, FA, Rugby Football Union and All-England Club – have publicly backed Covid passports as the safest way to get all fans back inside grounds as quickly as possible. In a letter sent to Boris Johnson, Keir Starmer and other party leaders, they warn that the government’s plans to have full stadiums will be impossible without some sort of “assurance process”. Their proposed solution is for all spectators to have a “Covid certification” – which would show that they had been vaccinated, recently tested negative or had antibodies. An added advantage, the letter says, is that it would “reduce and then safely remove the requirement for social distancing”. “All of our sports can see the benefit that a Covid certification process offers in getting more fans safely back to their sport as quickly as possible,” says the letter, also signed by the England and Wales Cricket Board, Football League and Silverstone. “We know that our stadia can only be fully filled with an assurance process. “This process must ensure that everyone can access stadia and must include arrangements that would verify a negative Covid test or an antibody test or vaccination certification.” Pilot schemes to allow fans inside some sports venues in limited numbers will begin next week, with the World Snooker championship at the Crucible able to have about 300 fans when it starts on 17 April. The following day an FA Cup semi-final is due to host 4,000 spectators and 8,000 have been allowed to attend the Carabao Cup final. The expectation is that all sports will be allowed to fill 25% of their grounds from 17 May. However the letter makes it clear that while the return of fans is welcome it “will still be insufficient to end sport’s Covid financial crisis” – and that there must be a robust plan for the return of full stadiums as soon as possible. Several sports have privately told the Guardian that the letter is also an attempt to make the public – and some politicians – understand that Covid certification would enhance people’s liberties by speeding up a return to normal life rather than restricting them. Some also expressed frustration that the messaging around Covid passports had been badly handled by the government and was undermining the argument for them. The letter accepts there is work to do on the technology, although one idea being kicked around is that the certificate would be contained on an NHS app that people would show when entering stadiums. A government spokesperson said they welcomed “the constructive approach from major British sports as we explore how testing covid certification and other steps can help get more fans back into stadiums and other large events safely”. “We want as many fans as possible to be able to enjoy a great British summer of sport safely,” they added.