David Cameron has promised to review "any individual case" relating to the so-called 'bedroom tax'.
Legal action will be launched against the plans today, which could see housing benefit payments reduced for tenants in council or housing association properties with empty bedrooms.
Under the new rules, all working-age tenants in receipt of housing benefit will be affected by the charge - 14 per cent for one unoccupied room, 25 per cent for two.
The charge would apply, irrespective of whether the room is occupied on a part time basis, such as a couple who use their spare bedroom if one of them is recovering from an illness or operation.
More top news
Speaking to ITV News Vince Cable ruled out a further sale of the remaining taxpayer stake in Royal Mail before the general election.
Expectations are high for David Cameron's immigration speech tomorrow in light of new migration figures showing an increase in UK migration
Two groups of Somali men have been found guilty of grooming and sexually exploiting under-age girls in Bristol. We tell the story