Tory No10 contenders Liz Truss and Rishi Sunak are being urged to dust off an old Labour plan to save £145million.
The Taxpayers’ Alliance pressure group says whichever one becomes PM should flog off four London government-owned buildings to help fund their spending pledges.
The scheme was last raised by Labour’s shadow Treasury Secretary Chris Leslie in 2014 when Ed Miliband was party leader.
He wanted to see Whitehall’s Civil Service Club, the QE2 conference centre near Parliament, Grade 1 listed Marlborough House, home of the Commonwealth Secretariat, and the Inn on the Park now St James’s Cafe sold to raise £103million.
But according to estate agents Foxtons property prices in the area have increased nearly 41% since then to produce today’s eye-watering figure.
James Roberts of the TPA said: “Ending subsidies for civil service perks and selling off unnecessary buildings will be supported by taxpayers of all political stripes.
“Tory leadership contenders looking to tighten belts in Whitehall would do well to pick up these policies.”
In 2014 Mr Leslie said: “Four such buildings in iconic locations in central London could attract interest from buyers around the world.
“A future Labour government will examine whether it would provide a better deal for taxpayers if the properties were sold off and the proceeds used to pay down Britain’s national debt.”
A Freedom of Information request by the TPA found that the Civil Service Club pays the Cabinet Office just £10 a year for their premises, with the current lease not set to expire until 2042.
Members pay £53 a year to join and can treat themselves to three course dinners of baked camembert with honey, white wine and sourdough for £5.95, an 8oz sirloin steak with sides and peppercorn sauce for £13.95 and a sticky toffee pudding at £4.95.
Wines start at £16.95 a bottle and a full English breakfast costs £5.95.
