The government was accused of chaotic mismanagement of the bedroom tax today, after it emerged it had no data about fundamental changes in home occupancy caused by the policy.
A series of parliamentary questions from Labour MP Frank Field showed the government has no idea how many tenants have downsized as a result of the policy, how many disabled people have had to move home or how many wheelchair users have been affected.
"How on earth can the government know how much money the bedroom tax will save when it doesn't even know how many people have downsized?" Field said.
"If disabled people downsize and need their new property to be adapted, this will end up costing the government more money.
"Likewise housing associations have warned that families may be forced to downsize into the private sector at a higher rent.
"This vicious policy isn't achieving anything other than hitting those hardest who can least afford it."
The absence of the information about house movements on the back of the bedroom tax – called a 'spare room subsidy' by the government – raises questions about arguments from ministers that the policy was designed to save money and free up existing stock to cut housing queues.
The government has argued that cutting housing benefit for tenants with extra rooms will push them into moving into more suitable accommodation.
Opponents say there is not enough housing stock with limited rooms, so the cut in benefits amounts to a tax on social housing tenants, given many have nowhere else to go.
There are also concerns about the policy's effect on disabled people, who often need the second room to store medical equipment.