Former Work and Pensions Secretary Iain Duncan Smith has attacked the Government's austerity programme, accusing David Cameron and George Osborne of balancing the books on the backs of struggling working people and the vulnerable.

In his first interview since his shock resignation from the cabinet on Friday, Mr Duncan Smith said cuts to welfare for working people had "gone too far" saying the Government risked dividing society with arbitrary cuts.

The former minister also said arguments with Downing Street and the Treasury had left him feeling "isolated" and "detached" with attempted cuts to welfare making him increasingly depressed.

He also suggested Conservative ministers were targeting benefits handed to working age people rather than pensioners because "they don't vote for us".

In an emotional exchange, he told the BBC's Andrew Marr he had no personal ambition, adding: "If I never go back into government again, I will not cry about that. I came into this government because I cared about welfare reform."

Duncan Smith resigned on Friday evening saying the cuts to disability welfare whilst offering tax cuts to the better off were “a compromise too far”.

Labour's Shadow work and pensions secretary Owen Smith said: "The Conservative Party is tearing itself apart over an unfair Budget. David Cameron and George Osborne's claim that 'we're all in this together' now lies in tatters.

"No-one will believe Iain Duncan Smith's sudden change of heart. After all this is the man who introduced the Bedroom Tax. But what his comments do reveal is growing anger within the Conservative Party about George Osborne's management of the economy.

"The Chancellor's unfair Budget is falling apart at the seams. George Osborne now needs to urgently clarify whether these cuts to disability benefits will go ahead and, if not, how he will make up for the huge hole in his Budget."