Politics really is a strange old business sometimes, isn't it? I mean, it's more than a year since the then Chancellor Gordon Brown announced the abolition of the 10p income tax band - so why did it take his dozy backbenchers so long to wake up?
True, a handful of people did see what was coming, but no one took much notice. Ming Campbell (remember him? Used to be leader of the Lib Dems) tried to draw attention to it; so did Frank Field; and so did the Institute for Fiscal Studies. A fat lot of good it did them.
And then suddenly, whoosh ... the balloon goes up. The genius magician chancellor, who had his backbenchers whooping in delight when he reduced the basic rate of income tax from 22p to 20p, is now the ham-fisted, accident-prone Prime Minister who can't seem to get anything right any more.
So I turned to two Labour MPs for elucidation. (They may not actually exist, these MPs, but if they did, I fancy they'd tell me something like this.)
First Labour MP: "Look, it's pretty simple, really ... I never understood a word of Gordon's budgets, and I don't know anyone who did, but cutting income tax by 2p sounded pretty good, even to me, and remember, this was when we were all just counting the days till we could get Tony out of Number 10 and turn over a new leaf. So I really didn't bother too much with all the small print. But y'know, suddenly over the past month or so, I've been getting all these constituents writing to me and turning up at my surgery on Saturday mornings, and boy, were they angry. 'What's the point of a Labour government,' they yelled, 'if all it does is clobber the poor? There's plenty of dosh for the dodgy banks, isn't there, but none for us.' Tricky, that, because I didn't have an answer. And with local elections next week, well, we had to do something, didn't we?"
Second Labour MP: "What did you expect, for God's sake? I always knew Gordon would make a lousy PM ... can't see the wood for the trees, and much too fond of all those incomprehensible tax and credit schemes he keeps inventing. So incomprehensible that even he doesn't understand them any more. Come on, we all know we're going to lose the next election, so let's get it over with. We've had a damn good innings, but Tony blew it in Iraq, and now it's time for the other lot to have a go. And you've got to admit, it's quite fun to see that big clunking fist get clunked itself for a change. The wretched man never took any notice of us when he was chancellor, but now he's a PM in trouble, he'll have to. If you think this week was messy, just wait. We've drawn blood, forced him to back down, and believe me, it feels pretty good."
This is the third time in recent months that Mr Brown has had to undo part of a Budget. He unscrambled Alistair Darling's capital gains tax reforms, which went down badly with the business world; he "clarified" his plans for taxing the non-doms (foreign nationals living in the UK but who are treated for tax purposes as if they aren't here at all); and now he's going to "compensate" young low paid workers and pensioners under 65 in ways which remain to be spelt out, so that they're not out of pocket as a result of his decision to abolish the 10p tax band (which, incidentally, he himself had introduced, with much fanfare, in 1999).
As for the local elections next week, they won't make happy reading for Labour, I suspect, although local election results rarely provide a clear picture. (Nor do snapshot opinion polls, necessarily, although today's YouGov poll in the Daily Telegraph, showing the Tories with an 18 per cent lead, isn't exactly a pretty picture for Labour.) If Boris Johnson wins the London mayoral election, it'll be bad for Labour but a mixed blessing for the Tories (just watch the forced smile on David Cameron's face as he congratulates the unpredictable Mr Johnson). And if Ken Livingstone does manage to hang on, Mr Brown will have to pretend to be delighted by the victory of one of the men he most hates in the Labour party (just ahead, probably, of Frank Field).
If I were Mr Brown, I might just be wondering if I should have called that general election last autumn after all. As I said, politics really is a strange old business.