On Thursday afternoon, the club's administrators, PKF, said they had received a new offer to purchase the troubled club from former Football League chairman Keith Harris to rival the PST bid.
The new consortium, fronted by Harris, investment banker Pascal Najadi and professional investor Alan Hitchins, said it was willing to offer the PST "a stakeholding and participation" if its bid was successful.
Despite the football financier wanting the fans' group to be involved in the proposed takeover, the Football League released a statement stating it will not consider any new offers after holding a meeting in London to discuss the plight of the south-coast club.
The statement read: "The League had previously been informed by PKF that its preferred bid for the club was from the Pompey Supporters Trust (PST) and all parties have been focused on a successful transfer of share to that consortium.
"Given that the Football League's Insolvency Policy prohibits a club from beginning two consecutive seasons in administration, the board took the view
that any change of preferred bidder at such a late stage would only create further uncertainty and was not in the wider interests of the League and its member clubs.
"Therefore, the League has informed the administrator that it will not currently consider transferring the club's share in The Football League to a new bidder.
"This means that in the event that the PST bid does not succeed and Portsmouth do not exit administration before the end of the current playing season, the club will lose its membership of The Football League."
The latest development comes a week before a High Court hearing is due to determine whether the League One club can be sold to the Portsmouth Supporters' Trust.
Earlier on Thursday, Harris told Sky Sports News the "cash offer" would leave the club debt-free and include the option to purchase Fratton Park from previous owners Portpin.
He said: "There would be neither legacy debt nor debt in our financing to acquire the club. It does not require a court hearing or anything else - it's straightforward, cash on the nail to buy the club.
"There will be no ongoing involvement by any previous owners. The transaction involves, initially, the leasing of Fratton Park but we've also entered into an agreement to acquire Fratton Park.
"That is our option, and the likelihood is it would be exercised at a very early stage."
The sale of Fratton Park, held as security by Portpin, has long been the major obstacle to the PST's proposed takeover.
Named as preferred bidder last year, the PST has been unable to agree a deal for the stadium and hopes the High Court hearing - three times adjourned already and now set for 14 February - will force Portpin to lower its asking price.
But the new offer has already been deemed "worthy of consideration" by PFK, and partner Trevor Birch said: "This offer could be completed without the need for a court case.
"We will need to discuss the terms of the deal with the PFA and the Football League and also plan to consult the creditors' committee as a matter of urgency. We will provide an update as soon as we have further news."
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