The so-called "bedroom tax" is reform to the way housing benefit is provided in England, Scotland and Wales. It is due to be implemented on 1st April 2013.
The Government calls it the "spare room subsidy" but it's also been referred as an "under-occupation charge".
The changes mean a cut to the amount of housing benefit people will receive if they are deemed to have a spare bedroom in their council house or housing association home.
People receiving housing benefit will have those benefits cut by a fixed percentage, which varies depending the number of extra bedrooms they have.
Those with one spare bedroom will have their housing benefit cut by 14 per cent. Those with two or more extra bedrooms will have their benefit cut by 25 per cent. Tenants on housing benefit will either have to make up the difference towards their rents themselves, or move in to smaller properties.
According to the National Housing Federation (NHF) which represents housing associations, the Government's impact assessment on the plans, " shows that those affected will lose an average of £14 a week. Housing association tenants are expected to lose £16 a week on average."
The NHF says the changes will affect an estimated 660,000 working-age social housing tenants and the majority of those will have only one extra bedroom.
On its website, the NHF lists the following groups who will be affected:
Separated parents who share the care of their children and who may have been allocated an extra bedroom to reflect this. Benefit rules mean that there must be a designated ‘main carer’ for children (who receives the extra benefit)
Couples who use their ‘spare’ bedroom when recovering from an illness or operation
Foster carers because foster children are not counted as part of the household for benefit purposes
Parents whose children visit but are not part of the household
Families with disabled children
Disabled people including people living in adapted or specially designed properties.
But some exemptions have already been agreed. For example, disabled children will not have to share with siblings.
Opponents of the plans say there are not enough houses with fewer bedrooms available for people to rent. They also claim the plans will mean an increase in rent arrears and could make people homeless.
The government says it wants to free up larger homes by encouraging people to downsize. It also wants to save millions of pounds in taxpayers money.