In an attempt to diffuse the row over planning reform, the PM is to announce the release of thousands of hectares of disused public sector, mainly brownfield, land to build 100,000 new homes, creating 200,000 new jobs by 2015. Developers would be allowed to use a "build now, pay later" scheme, by paying for the land only once the homes were sold. Mr Cameron pledged "the most ambitious growth plan that we could possibly have".
The National Trust estimates the total land bank with planning permission to be around 330,000 plots.
The figure is based on research by the Campaign to Protect Rural England (CPRE) which found that the biggest developers last year held land with planning permission for 281,993 homes.
Industry analysts say that many companies have added tens of thousands more plots to their stocks over the course of this year.
Bovis, one of the biggest developers, said earlier this month that it had bought 1,571 “consented plots”, and was buying another 2,500. Ministers say that England needs around 230,000 extra homes a year to meet demand. But according to the Department for Communities and Local Government (DCLG), only 124,000 new homes were completed last year. At that rate, the developers are sitting on more than two years’ building land.