The mayor of London Boris Johnson has said he will step in and ‘plug a funding gap after the government reneged on promises to fund homes in the capital’.

He said he believed the government is ignoring London’s acute need for more new homes by cutting its share of the affordable housing budget and diverting funds to the regions with comparatively less need to meet national short-term build targets.

Johnson said that in particular, north east England has seen its share of the housing budget double, ‘when it only has 300 households living in temporary accommodation, compared to 48,000 households in London’.

In a letter to John Healey, minister of state for communities and local government, the mayor expressed concern that the funding being diverted to other regions is largely being paid for by ‘raiding budgets set aside to upgrade over 100,000 of London’s poorest quality social homes’.

He said: ‘As mayor, it is my job to defend the capital's budgets and the city's poorest. I am looking at how I can use my powers to win back London’s rightful share of new housing funds, and reverse those decisions that condemn many of London’s poorest families to live in unacceptably poor conditions.

‘If the government will not live up to commitments made to council tenants, then I will guarantee Londoners that I will make up for these broken promises by reversing the government's decision and ensuring this funding gap is filled.’

The Mayor said that he, as chair of the London Homes and Communities Agency, nor London’s boroughs had been consulted over the proposed cuts. He said he believes the government may have acted outside its remit, set out in current legislation, and is seeking advice on whether the decisions taken are open to legal challenge.