The air base closed in May 2008 and operations moved to RAF Northolt
A council has asked the Treasury to help save plans for a World War II museum at an ex-RAF site in London.
The former RAF Bentley Priory site, in Stanmore, north-west London, was due to be sold for conversion into apartments and a museum by 2011.
But developer VSM Estates has been unable to sell the site, blaming the recession, putting the plan in doubt.
Harrow Council's head of planning Marilyn Ashton has asked the Treasury to consider funding the museum.
The air base, which was the command centre during the Battle of Britain, closed in May last year and its operations were moved to nearby RAF Northolt.
The site was sold to VSM by the Ministry of Defence (MoD).
A condition of the sale was that a museum be established on the site commemorating the efforts of Spitfire pilots in World War II.
An MoD spokesman said: "Unfortunately, negotiations with the previous preferred bidder were halted due to the current economic climate."
Miss Ashton has written to the Treasury, asking it to "help preserve the memory of Battle of Britain pilots by funding, directly or indirectly, a museum at the former site of RAF Command at Bentley Priory".
She added: "While I realise it is not the Treasury's role to intervene in private property deals, I do feel there is a broader issue at stake here as there is now real doubt over when - and if - the planned Battle of Britain museum will be built."
Miss Ashton asked the Treasury to consider funding the museum via a grant or a subsidy "that could make the site more attractive to private developers".
"The Prime Minister attended the D-Day commemoration event in France - I hope you would agree there is an equally pressing need here to safeguard the memory of those fighter pilots who helped preserve our freedom," she said.
The MoD spokesman said the museum was "an integral part" of the plan for the Bentley Priory site and that the inclusion of the museum/visitors centre in any future development "was secured".
"The MoD and VSM are working hard to find another developer," he added.