Developers are taking advantage of the new London mayor’s housing policy to try to reduce the amount of affordable homes they have to produce, according to former deputy mayor Nicky Gavron.

Gavron told the London assembly’s planning and spatial development committee that there was “anecdotal” evidence that developers were reducing the number of affordable homes on planned schemes.

Last week, mayor Boris Johnson confirmed his manifesto pledge to drop his predecessor Ken Livingstone’s target for 50% of new homes in London to be affordable. Instead the mayor said he would concentrate on ensuring the completion of 50,000 affordable homes in the city in the next three years.

Gavron’s comments were immediately rejected by Sir Simon Milton, who was this week confirmed as Johnson’s deputy mayor for planning and policy. He said: “The fact we’re removing the totemic 50% target doesn’t mean we don’t expect to maximise the affordable housing output – if necessary through the independent audit of development schemes.”

The exchange happened during Milton’s first appearance at the committee, which Gavron chairs. Gavron said the boroughs had relied on the mayor’s 50% target to enforce affordable housing quotas