A London estate was sold by a council for £50m even though it had spent £44m moving residents out, according to people who had lived there.
Southwark Council wants to redevelop the Heygate Estate in Elephant and Castle as part of a £1.5bn scheme to regenerate the area.
About 1,000 people have been moved from the estate.
The council said it was a good deal. Opponents have called the sale price a "shockingly low amount".
Councillor Fiona Colley, the council's cabinet member for regeneration, said the authority has a 50/50 profit sharing agreement with the developer Land Lease.
The mayor of London will also receive £15m towards transport redevelopment costs.
The figures were revealed after the council published documents on its website about the deal - however it did not redact commercially sensitive information properly.
People against the sale said the nearby smaller Oakmayne site, which is much smaller, sold for £40m.
Jerry Flynn, spokesperson for the Elephant Amenity Network which opposes this development, said: "It's a shockingly low amount for the size of the land the estate lies on.
"I think most people would be surprised it was sold for so little."
He added: "We support the regeneration of Elephant and Castle.
"However we don't believe this is going to bring the benefits that we were promised way back in 1999.
"I think the Labour administration is very anxious to see regeneration which is fine but it cannot be at any price."
The plans would see 2,500 homes at the Heygate Estate site while the regeneration would see 5,000 homes built across the whole area.
Mr Flynn, whose family had lived on the estate since 1974, said many people would not be able to afford the homes.
Ms Colley said the council wanted to spread affordable homes across the area rather than have them all in one place.
She said the regeneration would see 908 social rented homes and 715 shared ownership homes built, which was "no doubt more than replacing the number of homes" which were on the estate.
"Heygate is like a concrete fortress, built with enormous blocks designed to keep people out. We want to develop a mixed community," she said.
She said Land Lease was moving from planning to development and the council was due to debate a more detailed planning application.
The company has also started to advertise for people to buy homes.
A spokesperson for Land Lease said it had no comment.