Cheltenham's horse racing festival and Liverpool's Champions League game against Atletico Madrid are likely to have "increased suffering and death" by spreading in the UK, a leading scientist has claimed.
Professor Tim Spector, who leads the UK's largest coronavirus tracking project, said rates of cases "increased several-fold" locally following the events.
Cheltenham attracted more than 250,000 spectators to the event between March 10-13 while Liverpool played Atletico on March 11 in front of a crowd of 52,000.
The British Government said people should be allowed to attend despite other countries around the world cancelling events.
Professor Spector told the BBC the advice, based on the subsequent statistics, was the wrong advice.
He said: "I think sporting events should have been shut down at least a week earlier because they'll have caused increased suffering and death that wouldn't otherwise have occurred."
Around 3,000 Atletico supporters travelled from Spain to Liverpool for the second leg of their Champions League knockout match.
At the time, Spain is thought to have had more than 500,000 coronavirus cases, with Madrid being a hotspot of the disease.
It was the last major football fixture in England before the lockdown.
Cheltenham has previously defended the decision to go ahead with the sporting event in the south-west of England.
Organisers insisted the event "went ahead under the government’s ongoing guidance throughout".
Speaking in April, Dr Sue Smith, the festival's senior racecourse medical officer said: "It’s simply not possible to know how and where someone who has tested positive for COVID-19 has contracted it.
“The standards of hand wash and hygiene at the Festival were of the highest level and all measures were taken in accordance with daily updates from Public Health England.”
Liverpool could not have called their match of unilaterally or they face being disciplined by UEFA, European football's governing body.
They said: "Any decision taken by UEFA which led to matches being postponed or played behind closed doors was taken in close collaboration with, and based on decisions made by, the relevant national authorities in the respective host countries.
"UEFA did not receive any advice or request from local authorities to play this match behind closed doors."
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