Woodford Green MP Iain Duncan Smith has sensationally resigned as work and pensions secretary tonight citing pressure to make cuts to disability benefits.

Mr Duncan Smith’s shock decision comes just two days after controversial changes to Personal Independent Payments (PIP) announced in the Budget.

The £4billion of planned cuts to the benefit, which covers the extra costs of living with a disability, are expected to affect 640,000 people.

In his resignation letter, Mr Duncan Smith said he was “incredibly proud” of welfare reforms delivered by the government over the past five years.

“Those reforms have helped to generate record rates of employment and in particular a substantial reduction in workless households.

“I truly believe that we have made changes that will greatly improve the life chances of the most disadvantaged people in this country and increase their opportunities to thrive.

“I have for some time and rather reluctantly come to believe that the latest changes to benefits to the disabled and the context in which they’ve been made are, a compromise too far.

“While they are defensible in narrow terms, given the continuing deficit, they are not defensible in the way they were placed within a Budget that benefits higher earning taxpayers.”

He said he believed certain policies were “more and more perceived as distinctly political rather than in the national economic interest”.

“Too often my team and I have been pressured in the immediate run up to a budget or fiscal event to deliver yet more reductions to the working age benefit bill.

“There has been too much emphasis on money saving exercises and not enough awareness from the Treasury, in particular, that the government’s vision of a new welfare-to-work system could not be repeatedly salami-sliced.”