The mayor of London Ken Livingstone has called for an extra 8,500 homes to be built every year in the capital after an in-depth study of potential development sites.

Publishing the new London Housing Capacity Study (LHCS) which shows that from 2007 to 2017 there is capacity to build 31,500 new homes every year across the capital, the mayor said it underpinned his proposals to alter the housing provision targets in the London Plan.

The mayor intends to raise the target from 23,000 additional homes a year setting a new target of 31,500 a year. The study examined housing capacity across London and included an assessment of the housing potential of over 4,000 sites of over 0.5 hectares. It also included an extensive analysis of the potential housing capacity of smaller sites.

Using a new method of studying how building could be fitted onto the sites studied, the GLA says for the first time it has a real idea of how much room there is for housing development.

The study also tested a number of different policy scenarios and shows that the new housing can be delivered in line with existing plan policies to protect open space, retain land to support employment growth and ensure the sustainability of new residential development.

The mayor said: "London also has a huge backlog of housing need, particularly a need for more affordable housing."

The new LHCS examined all significant sites across the capital. The initial trawl covered some 4,464 sites over 0.5 hectares. Each site went through an assessment and validation process, which concluded that some 1,450 sites had some housing potential.

In addition, the potential capacity from smaller sites, provision of non self contained accommodation and from bringing long term vacant properties back into housing use were all given detailed consideration.

The initial analysis was then checked for consistency with London Plan policies on employment capacity, open space and other land uses and subjected to vigorous scenario testing to review impacts of factors such as noise, air quality and flooding.