London home building fell to 20-year low in 2009
Fewer homes were built in London last year than at any time in the last 20 years, according to government figures.
In all, work started on building fewer than 11,500 homes in 2009.
London mayor Boris Johnson pledged to deliver 50,000 affordable homes in the capital by 2012. His housing advisor Richard Blakeway said the target would be met.
However, housing expert Dino Patel warned deep cuts could worsen matters.
Mr Blakeway said: "We are on track to deliver the 50,000 affordable homes.
"We are improving the design standards for homes so they are a better quality home."
Mr Blakeway said work was being done to ensure regeneration schemes continued during "tough economic times".
Dino Patel, London regional manager at the National Housing Federation, said: "The global financial crisis and resulting recession have created a very difficult environment for developers.
"The government is intending to make huge cuts in every department including the communities and local government.
"We are urging the government to make sure that they do not make huge cuts because I think it will have a detrimental impact on future house building in London and the waiting lists will continue to grow."