London has only gained 13,585 additional homes for social and affordable rent, funded by City Hall, since 2008. Yes, even though the Mayor is very fond of saying that 50,000 homes have been (or will be) built in each of his terms, that doesn't take into account low-cost homes that have been demolished or sold off.
The Mayor's office has confirmed to Green Assembly Member Darren Johnson that London had 786,138 social homes in 2008 and, as of 2014, we had 799,723; 10,777 of which are 'affordable rent' (see our previous rant about that particular misnomer). What's happening is that new lower cost housing tends to be built during estate 'regeneration' — like what's happening at the Heygate, where nearly 1,200 social homes will be replaced by around 630 across the whole of the Elephant and Castle development, or the Aylesbury, which will lose 934 homes for social rent.
Funding from City Hall, via central government, is the main source of cash for 'affordable' housebuilding in the capital. Housing associations and councils will have built low cost housing of their own since 2008, but not on the kind of scale that will make much difference in that total net figure.
Darren Johnson said:
"With Right to Buy for housing associations on the horizon, and talk of more estate regeneration to come, we could see a large net loss of social housing in a city again. The Mayor should oppose these policies that erode the social housing stock, and lobby for a larger budget so the pressing need for genuinely affordable homes can be met."
You can watch the exchange between the two Johnsons at Wednesday's Mayor's Question Time below.