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
Revenge porn offenders who attempt to magnify their targets' humiliation will face the toughest penalties under new sentencing proposals.
A remarkably mild night with misty low cloud on the hills of Scotland, Wales and north-west England and further rain in places.
The former head of the Diplomatic Service breaks down the hidden meanings behind Theresa May's letter to Donald Tusk