Iain Duncan Smith has blamed Camden Council for the alleged “failure” of his bedroom tax policy in the borough.

The secretary of state for work and pensions introduced the policy as part of the government’s welfare reforms on April 1 last year.

But the removal of the “spare room subsidy” – dubbed the bedroom tax by critics – was labelled a “total failure” by Camden finance chief Cllr Theo Blackwell after figures showed only five per cent of Camden residents affected by the bedroom tax had moved to smaller homes.

The stated aim of the policy was to tackle under-occupancy of homes subsidised by the taxpayer.

Mr Duncan Smith said: “The question is for Camden Council. This is what they are meant to be organising, we gave them the money to do it and we gave them the flexibility to do it.

“The question should be, ‘Why aren’t you focussing on those who are in overcrowded accommodation? What about them? Isn’t there some requirement for you to get them into reasonable accommodation?’

“It’s not going to happen overnight but the point is to get better use of your housing here, you don’t want to have people living in houses that are way too big for them and at the same time people who are living in houses that are far too small for them and that’s the mismatch.”

Cllr Blackwell said: “The fundamental problem is that there aren’t enough smaller properties for people to move into. People are staying put and claiming discretionary housing payments.

“At some point it will run out and they will get further into debt. It’s a complete mess.”