Many moons ago, Charles J Haughey, Taoiseach of the 26 free counties, bestowed a great compliment upon an up-and-coming young Fianna Fail politician. Bertie Ahern, Haughey observed, was the coming force: "He's the man. He's the best, the most skilful, the most devious, and the most cunning of them all." Now, granted, that kind of praise was akin to Jimmy Savile suggesting you have a great future in children's entertainment but the point, nonetheless, was made. Bertie Ahern was a cute hoor who could cute and hoor with the best of them.

I often think of Haughey's praise for Ahern at this time of year. Because this is, invariably, the time of year when stocks in George Osborne soar to fresh and improbable heights. The Chancellor, people insist on claiming, is the cleverest, most dastardly, most devious, most adept political strategist of his generation. A veritable political genius, no less!

Well, maybe. For years now Osborne has made a virtue of missing his own targets. Targets - for debt and the deficit - are, it turns out, only numbers and George wants to be credited for good intentions, regardless of whether those targets are met. He is the Chancellor who demands a medal for participating only to then claim it's a winners' medal.

Now it may be that the markets reward this kind of rhetorical sleight-of-hand, this kind of nod-and-a-wink accountancy. It may be that a convincing appearance of intent matters more than the actual outcome. That, in this instance, Osborne is given greater leeway than a Labour chancellor would enjoy because his intentions are deemed, in some mysterious fashion, pure and decent whereas his opponents' bona fides would always be a matter of suspicion. I am sure it is the case. It still fails to butter the parsnip that is the fact Osborne has been, judged by his own stated standards and expectations, a dismal failure.

Failure, however, can be excused. It might be disagreeable but it is the stuff of life itself. Stupidity is less forgivable.

George Osborne is a clever man and the Treasury is stuffed with many other very clever men (and some clever women too). It is Whitehall's 'Big Brain' department and, consequently, irredeemably stupid.

Time and time again the Treasury comes up with wheezes so dumb and daft only very clever people could think of them. Sometimes these are relatively trivial - you may remember the pasty tax, for instance - but other times they are so obviously, head-in-hands, stupid you wonder how they ever made it into the outside world.

The tax credits fiasco was one such example of Treasury folly. Who could have guessed that taking £1,000 a year from two or three million working-class households would be so unpopular? I know! Scenes.

I'm reminded of a line from one of Michael Lewis's books. There was, you see, this Wall Street saying that whenever something was about to go belly-up you could bet it would do so with Merrill Lynch's fingerprints all over it: "There is going to be a calamity and whenever there is a calamity Merrill is there." You can say the same about the Treasury. Whenever there is a glorious clusterfuck, you know the Treasury will be there.

Sometimes these are, in the greater scheme of things, relatively minor clusterfucks. For instance, when it came to negotiating the new fiscal framework designed to underpin the new Scotland Bill, Treasury obstinacy turned an easy win for the UK government into a public relations triumph for the SNP. A wiser, less penny-wise-pound-foolish, Treasury would have understood that this was politics, not mathematics. But that kind of realisation would require a different kind of Treasury.

And now we have this latest fiasco over payments to the disabled. Now it is true that a government that plans to spend £17bn on Personal Independence Payments to the disabled cannot credibly be accused of stripping the welfare state to the bone. And it is also true that, despite the measures announced last week, this figure is an increase on previous figures. Nevertheless, a third thing is also true and that is that the latest plans, as announced by the Treasury, really do represent a cut when compared to previous PIP projections.

Surprisingly, this has proved controversial. Who could have guessed that cutting promises made to the disabled might - again! - disable the Chancellor's reputation for competence and political nous? I know! More scenes.

So a u-turn beckons. The damage is already done, however. Because, not content with taking money away from the disabled, the Chancellor also decided that this was the time to hand a £500 a year tax cut to people earning £45,000 a year while also - of course! - cutting capital gains tax for the (relatively) tiny number of people ever in any position to pay CGT.

Sure, £45,000 is not enough to be rich but, relatively-speaking, these people - especially if they live in two earner households - are doing pretty well. There is a significant difference between being well-off and being rich but when median full-time earnings amount to roughly £27,000 a year handing £500 to those on significantly more than that is going to strike many people as a questionable use of priorities. Especially when, gosh, the public finances remain a mess! Some people seem to be more in it than others.

This is the Tory party's original sin. It is perceived as being the party of the rich and time and time again goes out of its way to reinforce that negative stereotype. But, like most stereotypes, this one contains a decent dollop of truth. The party's instincts, too often, still favour the comfortably-off more than they do the ballyhooed strivers and aspirational working and lower-middle classes.

It's bad enough in times of plenty but unforgivable in more astringent times. Osborne, however, evidently lacks the imagination to understand how these matters will - rightly - be perceived.

There should be a rough but simple rule for Tory budgets: does this measure benefit people on or below £30,000 more than it benefits those earning twice that? If no, then don't do it. If yes, you can go ahead and do it. This should be elementary; that it isn't yet so is another reminder that the Tory modernisation project has not yet caught up with the reality of our times.

And it is another reminder that the future of the Tory party must be a blue-collar future not a stockbroker's future. One day Labour will come to its senses and be ready for government; when that happens Labour may deserve to win. Until then Osborne can bask in the false security of having beaten, first, a Labour party that presided over the worst economic crisis in more than half a century and then a Labour party led by Jeremy Corbyn. But this is akin to Barcelona boasting about beating Aston Villa; it doesn't tell you very much about either team.

Osborne is not the only part of the problem since his over-mighty department is also a large part of the problem but, really, when was the last time a politician was so untouchable for so long despite having so few achievements to his name? If George Osborne is a political genius, Lyndon Johnson was a pomegranate.

And, for that matter, he might pause to think on how Bertie Ahern's career ended. All the cunning and deviousness in the world is of little account if it leads you to financial - and moral - disaster.

UPDATE: Iain Duncan Smith's resignation - though he was probably for the chop after the EU referendum anyway - merely confirms the general thrust of my contention here.