Domestic football, from the Premier League to grassroots, will not take place in most of the UK this weekend after Queen Elizabeth II died aged 96.
Matches at all levels in England, Wales and Northern Ireland have been postponed, while in Scotland only senior games have been affected.
However, several other sports are continuing as planned, including cricket, golf, rugby union and horse racing.
What were the key factors behind football’s decision?
Dan Roan, BBC sports editor
After the Queen died on Thursday, football’s governing bodies convened on Friday to discuss the best course of action for the upcoming weekend’s fixtures.
The government’s national mourning guidance advised that cancelling games was not obligatory, leaving the decision to individual sports.
The Football Associations of England, Wales, Scotland and Northern Ireland all confirmed on Friday that fixtures would be postponed as a mark of respect.
The Premier League said the decision not to go ahead with its 10 games this weekend was made to honour the Queen’s “extraordinary life and contribution to the nation”.
In a rare example of unity, football’s authorities are understood to feel that – unlike other sports that have already paused events this week, like racing, cricket and golf – football has not yet had a chance to stop, reflect and show its respects.
Many people disagree of course, and feel matches would have provided fans with an opportunity to pay tribute. There is understandable sympathy for those who have spent money on tickets and transport, and now have to change plans at short notice, especially with so many other events in other sports going ahead.
The decision to stop grassroots and school sport is also contentious, especially after so much football was lost during the pandemic, even if it is just for one weekend.
But the FA is known to be mindful of football’s status as the national sport at this historic moment, and the close ties the sport had with the Queen, who was patron of the FA, while Prince William is its president.
What about next week?
With it being part of this weekend’s round of fixtures, Monday’s Premier League game between Leeds and Nottingham Forest was also called off.
But after that there are Champions League, Europa League, Europa Conference League and English Football League games taking place in midweek.
European games on Thursday evening went ahead as scheduled, with a minute’s silence observed in matches involving British teams.
Uefa has not yet provided an update on next week’s games involving British sides, but Manchester City’s Champions League game with Borussia Dortmund on Wednesday is due to go ahead as planned.
BBC Sport has been told City are able to provide the policing needed, so the game will take place as scheduled at Etihad Stadium.
Rangers, who host Napoli in the Champions League on Tuesday, said in a statement they are in discussions with Uefa but “at present, the game is scheduled to take place at the scheduled date and time”.
Manchester United have confirmed their Europa League game with FC Sheriff in Moldova next Thursday will take place as scheduled “following discussions with the relevant governing bodies and in line with guidance issued by the UK government”.
The EFL has not yet issued an update yet on its round of midweek games.
As for next weekend’s fixtures, they are currently taking place as planned although that could change depending on when details of the Queen’s state funeral are provided.
The funeral is expected to take place at Westminster Abbey in less than two weeks, but the exact day will be confirmed by Buckingham Palace.
If it takes place next weekend then fixtures could again be postponed. Policing games could be a factor in the decision if they are redeployed to London en masse before the Queen’s funeral.
There are currently three matches scheduled to take place in the capital over Saturday and Sunday. The Premier League is understood to be talking to its clubs, while the Metropolitan Police has been asked for a comment.
Tottenham play Leicester on Saturday evening, while Brentford face Arsenal and Chelsea are at home to Liverpool on Sunday 18 September.
When will the postponed games be played?
Simon Stone, BBC Sport
Finding room in the packed English football calendar for a full round of Premier League fixtures (and possibly two) is going to be complicated.
In a unique season that includes a winter World Cup – and restarts on 20 December with the Carabao Cup fourth round, space is severely limited.
There is no spare midweek from now until the season ends on 3 June that exists without a purpose.
Two, 17 January and 7 February, are for FA Cup third and fourth-round replays. Three more, 4 April, 2 May and 23 May, are for matches that have been postponed on the weekends of the EFL Cup final and the FA Cup sixth round and semi-finals.
Two January midweeks are for the individual legs of the EFL Cup semi-finals. Eight midweeks are reserved for Uefa matches – and the European governing body is resistant to domestic games being played at the same time as its matches. And two midweeks in March form part of the final mid-season international break.
Discussions will start next week about how to resolve the issue. The respective governing bodies are relaxed about the situation given they dealt with similar calendar issues during the 2020-21 Covid-19-affected season.
Then, FA Cup replays were scrapped and the EFL Cup semi-finals were played as one game.
Answers will be similarly difficult now.
What has been the reaction of fans?
The Football Supporters’ Federation accepted there was “no perfect decision” for the football authorities, but added it believed many supporters would have wanted games to go ahead.
It said in a statement: “We believe football is at its finest when bringing people together at times of huge national significance – be those moments of joy or moments of mourning.
“Our view, which we shared with the football authorities, is that most supporters would have liked to go to games this weekend and pay their respects to the Queen alongside their fellow fans.
“Not everyone will agree, so there was no perfect decision for the football authorities, but many supporters will feel this was an opportunity missed for football to pay its own special tributes.”
What’s happening in other sports?
Play will resume in England’s cricket Test against South Africa on Saturday, and the women’s Twenty20 match between England and India will go ahead.
Golf’s PGA Championship will restart on Saturday after play was halted on Thursday.
Sunday’s Great North Run will go ahead as planned, with organisers saying it is “an opportunity to come together and express our condolences while celebrating the life of our extraordinary Queen”, and that the event would be “more subdued out of respect”.
Boxing’s world title fight between Savannah Marshall and Claressa Shields on Saturday has been postponed, with a provisional date of 15 October set for it to be rescheduled.
All British Boxing Board of Control tournaments have also been postponed for the weekend.