In one of the most extraordinary political interviews of recent times, Iain Duncan Smith has warned that the government ‘is in danger of drifting in a direction which divides society rather than unites it.’ He repeatedly, and pointedly, argued that in drawing up policy the Tories have to have a care for those who don’t, and will never, vote for them—a remark that everyone in Westminster that will see as being directed against George Osborne.

Explaining his resignation, IDS that he was ‘semi-detached’ from decisions taken in government, and that his department was being forced to find savings because of the welfare cap which had been ‘arbitrarily’ lowered by the Treasury. He declared that what made the disabled benefits cuts so unacceptable to him was that they appeared in a Budget that also cut tax for the better off.

IDS’s central argument is that areas other than working age benefits need to be looked out for savings if the deficit is to be reduced fairly. He was explicit that he no longer supports the continued triple lock for pensions and the protection of pensioner benefits.

This interview was an attack on Cameron and Osborne’s claim to the one nation mantle. I suspect that Numbers 10 and 11 will be incandescent about it—Amber Rudd, an Osborne ally, has already declared that she resents IDS’s ‘high-moral tone’. They’ll also be furious that IDS wasn’t pressed on Europe at all. Though, the passion with which IDS spoke suggested that welfare policy really was the reason for his resignation. Though, I suspect that the EU referendum—and the nature of it—has made IDS more prepared to break with Cameron and Osborne than he would otherwise have been.

Labour will now be able to attack the government and the deficit reduction programme as too right wing for even Iain Duncan Smith to support. Labour will warn that every controversial measure the government introduces is, to use IDS’s phrase, ‘dividing society’. To undo the damage done by this attack, Cameron and Osborne will have to show that this really is a one nation government in both motivation and deed.