Hundreds of “rabbit hutch” flats built in Lewisham under relaxed Government rules are unaffordable and a number flout minimum space standards, new research has shown.

In 2013, the government changed the rules to allow developers to convert office space into flats without planning permission.

Under the rules, 309 flats have been built – none of which were affordable, Lewisham and Greenwich London Assembly member, Len Duvall, explained.

And looking at energy use in 79 of the flats, 34 of them flouted minimum space standards.

This could mean as many as half of the 309 homes don’t meet the standards.

He said: “This flawed Government policy is hampering the efforts being made to tackle the acute housing crisis faced by Lewisham.

“Permitted Development doesn’t offer a solution to housing shortfall, it just forces families into sub-standard, rabbit-hutch homes,” he said.

This comes as the Government announces further reform, including allowing larger home extensions without planning permission.

Mr Duvall said the rules were concerning and could create the “slums of the future.”

“Planning standards have been put in place for a reason, and our priority should be to build the thousands of genuinely affordable and decent quality homes that Londoners need,” he said.

“All the evidence suggests that the Government need to scrap this policy as a matter of urgency”.

Mayor Damien Egan, said Lewisham Council had applied to be exempted from the rules but was not successful.

“Lewisham Council sought exemption from the Government when they introduced these rules as we could see that they were wrong, and would mean the council has no say over developers converting office space into expensive micro units,” he explained.

“The Government urgently needs to scrap these housing rules so we can tackle the housing crisis in Lewisham and ensure that everyone has somewhere decent and affordable to live.

“I fully support Len Duvall’s campaign on scrapping Permitted Development rights,” he added.