'Under-occupancy charge is not a tax' says PM
6 March 2013 Last updated at 14:03 GMT
The Prime Minister has been defending the coalition's "under-occupancy charge", which has been dubbed "bedroom tax", at Prime Ministers Questions.
Responding to a question from Derek Twigg MP, David Cameron said, "Only Labour could call a benefit reform a tax increase...pensioners are exempt, people with severely disabled children are exempt, people who need round the clock care are exempt."
Under reform plans, social housing tenants' benefits will reduce if their home has one or more spare bedrooms.