London Irish have been granted an extension until June 6 to meet the RFU's criteria for survival as a Premiership club.
The RFU announced on Wednesday evening its Club Financial Viability Group has agreed to give the club an extended deadline of one more week to meet their conditions but that this deadline will be final.
The club is £30m in debt and has been in talks with an American consortium over a takeover.
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The RFU has stipulated that two either the takeover has to be completed and approved by Tuesday June 6 - an extension from Wednesday night, which was already a further 24 hours on from the RFU's original deadline - or the club has to produce evidence it could be funded and operated throughout the entirety of next season.
The club must also pay this month's remaining payroll to staff and players.
Failure to meet these conditions will see London Irish suspended from top-flight rugby.
The RFU stated that this extension until June 6 has been granted following consultation with staff and players who asked for the deadline to be extended to allow them to be paid the remaining 50 per cent of their May salaries.
On Tuesday, ahead of the original deadline, the American consortium in discussions to take control of the club had yet to provide proof of funds to the RFU, as well as other documentation needed for the purchase to be approved.
Paula Carter, RFU board member and chair of the club financial viability working group said: "It is deeply frustrating for all the staff, players and fans that there have been months of multiple missed deadlines.
"We are extremely disappointed that the club has so far only funded 50 percent of the staff and player wages, however, we have to respect the wishes of those most affected.
"The 4pm deadline on June 6 is final and we have added the stipulation that the club must also fulfil its contractual obligations to its employees by paying the May salaries in full."
London Irish had finished fifth in this year's Gallagher Premiership, just outside of the play-offs.
Yet despite that relative success on pitch they are on the brink of following in the footsteps of Wasps and Worcester, who both went into administration late in 2022 and were expelled from the league.
They could become the third club to be kicked out of the English Premiership on financial grounds in seven months.
Employees of the club received their April pay a week late and the club had to cover their salaries, with payments eventually going through two days prior to their final match of the Premiership season against Exeter Chiefs. The players also demanded proof that their insurance premiums had been covered before taking to the field for that match.
Under RFU rules, players can leave their clubs for free if they are not paid within 14 days of their scheduled payment date of wages.