England's Test series in Sri Lanka has been cancelled due to the growing threat of the COVID-19 pandemic and their home series against West Indies in June - as well as the T20 Blast - is under threat, with both events scheduled for a period that the UK government has identified as the likely peak of the virus in the country.

Prime Minister Boris Johnson confirmed at a press conference on Thursday afternoon that sporting fixtures will not be banned with immediate effect, but said that such a move is under consideration, which could wreak havoc with the English cricketing summer.

England confirmed the series in Sri Lanka had been postponed on Friday, walking off the field on the second day of their tour match against a Board President's XI moments after the decision was announced.

"Due to the Covid-19 pandemic worsening globally, and after discussions with Sri Lanka Cricket, we have today made the decision to return our players to the UK and postpone the forthcoming Test series between Sri Lanka and England," a statement read.

"At this time, the physical and mental wellbeing of our players and support teams is paramount. We will now look to bring them home to their families as soon as possible. These are completely unprecedented times, and decisions like this go beyond cricket.

"We would like to thank our colleagues at Sri Lanka Cricket for their outstanding support and assistance throughout this situation. We look forward to returning to Sri Lanka in the very near future to fulfil this important Test series."

The global sporting calendar has already been thrown into chaos by the spread of the virus, with hundreds of events postponed, cancelled, or played behind closed doors. In England, four counties have cancelled their pre-season tours overseas, while at least two more are expected to return home early.

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Sir Patrick Vallance, the UK's chief scientific adviser, said during the Prime Minister's press conference that the peak is "10-14 weeks away, maybe slightly longer", leaving the English cricket season in a nightmare situation which could result in a huge number of fixtures cancelled or played behind closed doors.

England are scheduled to play three Tests against West Indies, with the series starting at The Oval on June 4. That date is currently 12 weeks away, in the middle of the expected peak period. The T20 Blast is scheduled to start on May 28, with the group stage running until July 12.

"We are considering the question of banning major public events such as sporting fixtures," Mr Johnson said, describing the virus as "the biggest public health crisis in a generation".

"The scientific advice, as we've said over the last couple of weeks, is that banning such events will have little effect on the spread," he said.

"But there is also the issue of the burden that such events can place on public services, so we're discussing these issues with colleagues in all parts of the United Kingdom. We'll have more to say shortly about further action in that respect. At all stages we have been guided by the science, and we will do the right thing at the right time."

The cancellation of a whole home Test series would be a significant financial blow for the ECB, while the T20 Blast generates a major proportion of most counties' income. It is possible that the tournament could be pushed back further in the summer - possibly at the expense of the final rounds of County Championship fixtures - but there is precious little room in the schedule for change.

More immediately, the County Championship is scheduled to start on April 12. While crowds are typically relatively low, they regularly exceed 2000 at certain grounds, and the main demographic of match-going fans is elderly, increasing their vulnerability to the virus.

It is possible that games - almost all of which are streamed for free online - could be played behind closed doors, and the ECB is in close contact with government to discuss its options.

Sir Patrick explained that the nature of the virus means that a blanket ban on sporting fixtures is unlikely to have a major impact on its spread. "On average one person infects two or three others," he said. "You therefore have a very low probability of infecting a large number of people in a stadium, or a rather higher probability of infecting people very close to you.

"And that means that most of the transmission tends to take place actually with friends and colleagues in close environments, not in the big environments. So, it is true, of course that any cancellation can have some effect.

"But if you get a displacement activity where you end up with everyone congregating somewhere else, you may actually have perversely an increased risk, particularly in an indoors environment."