THE GOVERNMENT is set to blow taxpayers’ cash on a costly legal challenge to Wednesday’s landmark court ruling that the bedroom tax is discriminatory and illegal.

Court of Appeal judges found that the notorious policy “discriminated” against a domestic violence survivor and the family of a severely disabled teenager.

Labour raised an urgent question in Parliament yesterday morning to push for other social housing tenants with similar cases to be exempted immediately.

But Tory Work and Pensions Secretary Iain Duncan Smith ducked scrutiny over the humiliating court defeat.

Instead junior minister Justin Tomlison was left to tell MPs that the government is ready to try to overturn the ruling in the Supreme Court.

Ignoring shouts of “shame” from opposition MPs, he argued that singling out vulnerable groups for exemption was not practical — even claiming they would be worse off.

The government has pledged to spend £870 million over the next five years to offset the £16-a-week housing benefit cut for Britain’s most vulnerable social housing tenants. 

Mr Tomlison told MPs: “If we try to set strict categories, people — especially those with unique circumstances and issues—could fall just below an artificial line, meaning that they would miss out.

“Is it realistic to expect that here in London we could set such an exhaustive list?”

But shadow work and pensions secretary Owen Smith said it would cost just £200,000 to exempt 280 victims of domestic abuse who are affected by the policy.

The case on Wednesday involved a woman referred to as “A” who lives in a council house adapted to contain a panic room to protect her from a violent ex-partner.

Mr Smith said the sum needed to protect such tenants was tiny compared to the “blank cheque” Mr Duncan Smith was preparing to write to fund the government’s legal challenge.

And in a powerful rebuke to his Tory counterpart, Mr Smith concluded: “Politics is about choices, and the choice that faced the Secretary of State today was very clear.

“He could have come to the House and admitted that this was a rotten policy that was punishing poor people across the country, and he could have scrapped it.

“Instead, he is sitting on the front bench before going back to Caxton House to consult his lawyers in order to defend this policy against the victims of domestic violence and the parents of disabled children. We know the choice he took.”

Paul Rutherford, the grandfather of the disabled teenage boy involved in Wednesday’s court victory, called for the government to respect the judges’ decision.

Labour MP Liz McInnes asked: “I just want to put a simple question asked by Mr Paul Rutherford himself — why are the government spending taxpayers’ money on an appeal?”

Mr Duncan Smith repeatedly refused to come to the despatch box to answer the question, leaving Mr Tomlinson to claim: “Because we want to ensure that those who are vulnerable get the right support.”

SNP MP Ian Blackford branded him a “disgrace” for “whispering into the ear of his minister” instead of answering the questions.

“He is quite clearly out of his depth on this, as he is on so many other things.”