Coalition ministers already have evidence the 'bedroom tax' is not saving money and should scrap the controversial policy, Labour have said.

The call follows comments by Scottish Secretary Alistair Carmichael that the housing benefit cut could be abolished if a review finds it is not delivering cost savings.

Labour's shadow Scottish Secretary Margaret Curran pointed to figures from the Convention of Scottish Local Authorities (COSLA) that in Scotland the bedroom tax could cost at least £58 million and save only £50m.

In a letter to Mr Carmichael, she wrote: "It is clear that the evidence you are looking for already exists. Instead of waiting for the conclusions of your Government's review, which will come only after tens of thousands of people have been affected and housing associations and local authorities have borne the brunt of your Government's policy, you should scrap the bedroom tax now."

The government-ordered review is due to report after the 2015 general election.

The Department for Work and Pensions believes the bedroom tax will reduce the housing benefit bill by around £500m a year.

But a recent University of York report suggests the DWP has over-estimated the savings by as much as 40%.

Ministers have defended the policy saying it will help ease overcrowding.