Rugby Football Union (RFU) chief executive Bill Sweeney warned of the "catastrophic" impact coronavirus could have on the sport if the professional game cannot return in the next year.
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Sweeney revealed England's RFU, which has already lost £15 million due to the crisis, will lose a total of £107 million if the autumn internationals are cancelled.
The prospect of also having to postpone or play next year's Six Nations Championship behind closed doors is even more stark.
"Eighty-five percent of our revenues come from hosting men's internationals at Twickenham," Sweeney told a meeting of the UK's Digital, Culture, Media and Sport (DCMS) committee on Tuesday.
"If this was to be prolonged and go into the summer of next year and the Six Nations games were impacted then it would be a catastrophic impact on rugby union in England.
"If we get into a situation where we are talking about Six Nations matches next February/March being impacted then there is a limit to what we can do independently. We would have to be coming to government for some kind of support."
English Football League (EFL) chairperson Rick Parry and England and Wales Cricket Board (ECB) chief executive Tom Harrison also spelled out the gravity of the financial crisis facing their sports to politicians.
The ECB's controversial new Hundred competition has been delayed until 2021 and even if Test matches can go ahead later in the summer, they are likely to be behind closed doors.
"We anticipate with no cricket this year a worst-case scenario could be as bad as £380 million," said Harrison on the loss of revenue faced by the ECB.
"That would be the loss of 800 days of cricket across all of our professional clubs and the ECB. That is the worst-case scenario for us this year."
England were due to host the West Indies and Pakistan in Test matches this summer.
However, the West Indies series has already been delayed with professional cricket postponed until at least July.
"Hopefully we will be able to play a significant number of Test matches this summer which will help us mitigate those financial losses that we are facing at the moment," added Harrison.
The prospects for football clubs below the Premier League are also dire with lower leagues much more dependent on gate receipts than the top tier.
Premier League clubs are hoping to forge ahead with their "Project Restart" with the aim of salvaging £762 million in television deals for the remainder of this season alone.
By contrast, Parry believes it would cost clubs in his organisation to put games on behind closed doors.
"We are heading for a financial hole of about £200 million by the end of September," said Parry.
"We have a great deal of uncertainty around next season of course, the great undetermined matter being when we're going to return to play in front of crowds, which for the EFL is absolutely critical."