London Irish became the third rugby team to be thrown out of the Gallagher Premiership in eight months after the Rugby Football Union (RFU) said the club had failed to pay their players and prove they had a financially viable future by Tuesday's deadline.
London Irish filed for administration after the club's suspension from the Premiership was confirmed.
The club had been given a week's extension to show evidence of a proposed takeover by an American consortium or that they had the finance in place under current owner Mick Crossan to continue through the 2023-24 season.
However, they failed to do so or to fully pay their players and staff by Tuesday's 3 P.M. deadline and the RFU duly announced that the club would not be able to participate in any league next season.
The RFU said in a statement: "The decision was taken after six months of talks to take over the club failed to materialise and to provide certainty to staff and players, thereby allowing them to seek alternative employment. The move also provides clarity to other clubs in the league and prevents a situation where the club goes into administration part way through a season."
"The RFU, Premiership Rugby and the RPA (Rugby Players Association) have been in regular dialogue with the club to support the takeover and provide regular updates to players and staff.
"Today the three organisations have announced they have launched a hardship fund for players and staff who are most in need of financial support. The fund will also be available to those in need following the Wasps and Worcester insolvencies."
The RFU's club financial viability group had agreed to the extension at the request of players and staff, who were paid only half of their May salary last week.
Last Friday the club were served three winding up petitions by the Government's tax authority HMRC, following the path of Wasps and Worcester, who went into administration late last year.
Irish finished fifth last season, their best placing since 2009, but their demise has again exposed the financial struggles afflicting the professional game in England where limited TV and ticketing income struggles to support huge playing squads.
Irish have been ground sharing with Premier League football club Brentford in west London and have reported debts of around £30 million.
RFU CEO Bill Sweeney said: "This is desperately sad news for everyone who is part of the London Irish community as well as all the players, fans, staff and volunteers for whom this club means so much.
"Our collective first priority has been to do the utmost to secure the long-term viability of the club and the protection of its players and staff."
The RFU said it would also ensure that the professional club's youth academy would continue.