Fans will not be allowed to attend the pilot sports events scheduled for this weekend in England after a spike in coronavirus cases, UK Prime Minister Boris Johnson has said.
Spectators were due to watch the first two days of two county cricket matches, while 205 fans were at the start of the World Snooker Championship on Friday.
It was also hoped to allow 4,000 racegoers at Goodwood on Saturday.
The new restrictions on fans will be enforced until at least 15 August.
The announcement comes after general restrictions were reintroduced for people in parts of northern England.
"Pilots of larger crowds at sports venues will not take place," Johnson said at a news conference on Friday.
"I said from May we would not hesitate to put on the brakes at the slightest sign that the numbers were going in the wrong direction."
Johnson had said earlier this month that spectators could be able to return to stadiums in England from October.
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The planned pilots - and reaction
Fans were already at the World Snooker Championship in Sheffield when the prime minister spoke on Friday, with announcer Rob Walker shouting "we are back" as play started, before adding: "Our socially distanced crowd are poised to roar once more."
World Snooker chairman Barry Hearn was shown smiling, clapping and fist-pumping, as spectators - some wearing masks - cheered on the first players Judd Trump and Tom Ford.
Just hours earlier, Hearn had told BBC of his "pride" and "relief" at getting fans back at events.
However, while those with tickets for Friday's further sessions were allowed to stay, there will now be no spectators permitted at the Crucible Theatre from Saturday. Fans with tickets will be given a refund, or be allowed to use them next year.
After the government decision, Hearn told BBC Sport he was "gutted" and "disappointed" to not have an atmosphere, but added: "The show must go on.
"There is a chance - I'm forever the optimist - that maybe a return for the final [on 16 August] is the earliest possible opportunity.
"Congratulations to those guys who went today because they will be able to talk about this for the rest of their lives - the ultimate golden ticket.
"I've never known a circumstance change in a couple of hours, but that is symbolic of what is happening in the world at the moment.
"We don't go off into a corner or go into sulks or tears, we get the job done."
Two matches in cricket's Bob Willis Trophy starting on Saturday had been due to welcome spectators - Surrey v Middlesex at the Oval and Warwickshire against Northamptonshire at Edgbaston.
The England and Wales Cricket Board (ECB) said: "We understand the reasons the government has made this decision, and remain ready to work with them to ensure supporters can safely return to stadiums when government advice allows.
"We are pleased the Bob Willis Trophy will still begin this weekend behind closed doors, and fans will be able to watch their teams in action through the online streams being provided."
The Oval had been due to host 2,500 fans on Saturday and Sunday, having held the first pilot last weekend of 1,000 fans.
Surrey chief executive Richard Gould said: "A lot of hard work has taken place to ensure that members and fans could return to our ground safely.
"We still hope to welcome members to the ground for future matches this summer, and we will continue to work with the ECB and the government to encourage this to happen."
A statement from Goodwood racecourse said: "We are very disappointed for those who were hoping to attend tomorrow's event and for all those who have worked so hard to make it possible for spectators to be present.
"We will engage with public health authorities and the DCMS (Department for Digital, Culture, Media and Sport) over a rescheduled pilot at the earliest opportunity."
Culture Secretary Oliver Dowden posted on social media that it was "very disappointing news".
"I know the huge efforts cricket, snooker and horseracing have made to welcome fans back. We'll keep working together on their safe return ASAP," he added.
BBC sports editor Dan Roan
This will be hugely disappointing news for the events involved, and obviously very worrying for the wider sports industry, which is increasingly desperate to get paying fans back through the turnstiles to ease an unprecedented financial crisis - especially for those sports bodies dependent on matchday revenue, like English Football League clubs.
Until now, the effort to get sports back up and running after lockdown had gone relatively smoothly, with the football season resuming and now almost completed, along with other events such as Test cricket, Formula 1 and horse racing.
This then is a first major setback in the wider effort to return sport to some kind of normality.
However, crucially, I am told by Whitehall sources that the government remains keen to work with sports and Public Health England with a view to getting fans back inside venues from 1 October.
Some sports organisations - like the Premier League - would like to see that target date brought forward, but Friday's news will not have helped them win that argument.
Attendances of 20% to 40% capacity - depending on the nature of the venue - is envisaged by officials from October, and more pilots are being planned in the coming weeks.
It is simply too early to tell whether this is now unrealistic. It remains the aim but there are no guarantees.
This is a stark reminder that the nature of the pandemic means it is difficult to plan months in advance, and that officials will need to take decisive action when data shows worrying trends.
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