Iain Duncan Smith, the former Work and Pensions Secretary, has told ITV News he had no choice but to resign in order to push the government into pursuing a fairer welfare policy.
Speaking to ITV News' political editor Robert Peston, Mr Duncan Smith said his department was under enormous pressure to meet arbitrary targets which unfairly placed the burden on struggling working people and the vulnerable.
The former minister resigned on Friday evening saying that pairing back disability benefit while offering tax cuts to the better off was "a compromise too far".
"I think I can't do this any longer inside, I have to go out, resign and argue for this kind of process outside," he said.
Mr Duncan Smith called suggestions he had resigned to campaign for Britain to leave the European Union "Machiavellian".
"If I was that clever and intelligent I would be incredibly proud of an assertion that was completely wrong," he said.
"My resignation note was straightforward."
Downing Street has responded to Mr Duncan Smith's resignation saying the government is delivering the welfare cap, a key part of the Conservative's manifesto.
Prime Minister David Cameron has said he was "puzzled and disappointed" by Mr Duncan Smith's decision to resign.