The Tories are already widely regarded as deeply unfair; but up until now, they have been seen as competently unfair. According to a poll in 2013, just over half the population agreed that “the Conservative party only represents the interests of the rich”. That means a party that half of us believe is the political wing of rich people still managed to win a general election. Granted, the Tories only won over 36.9% of those who voted, but it is likely at least some of those who believe the Conservatives effectively exist to promote the interests of the rich voted for them.

And that’s why “shambolic” and “incompetent” have to be firmly associated with the Tory brand. No, that doesn’t mean retreating from the charge of unfairness. For years the left has made the following case: firstly, that cuts to social security are ideologically driven, rather than motivated by what is best for the people affected and the country as a whole; secondly, that they have hurt the poor; and thirdly, that they make a nonsense of the claim “we’re all in it together”. And those lines of argument – long derided by the right – have now been echoed by the Tories’ former social security supremo, Iain Duncan Smith himself. His lines have to be repeated ad infinitum: because we have been vindicated, and a direct appeal can now be made to Tory voters.

But it is their own incompetence that truly poses a threat to the Tories. George Osborne’s whole approach has been to put political positioning ahead of the interests of the country. He has failed by every substantial measure – the deficit, debt, growth, living standards, productivity, you name it – and yet, for a long time, has been presented as a strategic genius. It was beyond careless to attempt to introduce cuts to tax credits, and then be forced into a partial U-turn. But to be forced to withdraw a key plank of a budget within days – a cut to disability benefits – while frittering away money on higher earners, and in doing so provoke the resignation of a key cabinet member: well, incompetent doesn’t cover it.

If a perception of unfairness alone was enough to displace the Tories from power, they would have been ejected from Downing Street by now. Yes, the cuts have gone so far that, maybe, they are beginning to eat into public acquiescence. And yes, Duncan Smith’s own words need to be thrown back at the Tories. But, for the first time since the Tories came to power, there is an opportunity to make the charge of incompetence stick. It must not be missed.