Owners of Kensington Odeon have put it on the market for £85million, four years after buying it for £24m.
Project managers Northacre and developers Minerva joined forces to revamp the Kensington High Street site in 2005.
Since then, they were granted planning permission to turn it into 35 flats, five townhouses and a six-screen cinema, boosting its value further.
A development of this size would normally involve a compulsory element of affordable housing for the developer,but Minerva and Co persuaded the council it would be financially unsustainable to include it on the site.
The selling price, reported in trade paper Estates Gazette, has caused anger among councillors and residents, who feel duped by the partnership's original claims of poverty.
"It is infuriating that the developers told us there was too little profit in this to put affordable housing on site," said a Royal Borough council-lor, who asked not to be named.
"Perhaps £50m is too small a profit for them."
Kensington Society planning chairman Michael Bach said the council had missed an opportunity to make the developer build affordable housing.
"'Developers' convince the council and get around building affordable housing because they would prefer not to do it, but then they sell it for a huge amount of money," he said.
"This is not an isolated case. The council appears to have been rather easily persuaded and, if it had not been, things might have been different. Once planning permission is granted that's it."
Planning consultants Montague Evans, working on behalf of the co-owners, confirmed the site had gone on sale for a guide price of £85m.
The consultants, which handled the original planning application, rejected suggestions that Minerva had got away without including affordable housing.
"There is affordable housing as part of the planning permission, for 30 units, but not on site," said surveyor Jo Fone. "It will be on a location to be decided and within an agreed timescale."
Montague Evans said the new owner would have to honour the commitment to build new affordable housing on a separate piece of land.