Yet to hear from Labour what they will do if they are the wrong side of the Laffer curve and get less money than the expect, and more like the money the IFS predicts, more tax or more borrowing?
I have no idea - I'm not in charge of Labour's economic plans and I am sceptical of them to say the least.
Pure speculation, but if they failed to bring in the tax receipts they suggest then they'd probably ditch some of the more costly and less priority pledges, while additionally raising tax more generally on those earning below £80k. Plus they'd probably borrow a bit more too. None of these would make them popular.
So reverse question to you - yet to hear from the Tories what they will if they are the wrong side of the Laffer curve and get less money than the expect, and more like the money the IFS predicts, more tax or more borrowing?
The question is equally valid for them as their proposals (according the IFS) are also poorly costed.
But there is a broader question, which is that however well plans are made they are merely that, projections of tax receipts and spending in the future, which can prove to be wrong because of 'events dear boy', even with sensible planning. Governments and chancellors have to have the discretion to change planning and priorities to deal with changed circumstances, which is why crude pledges of 'not raising income tax etc' - while seeming to be good in sound bites merely mean that government's end up fettering their discretion and having to raise the same amount of tax, probably from the same people, via backdoor routes.
Frankly what matters to me (and probably to most people) is the total tax take. I'm not going to be happier if my take home pay is reduced to the same extent because of a 1% increase in NI rather than a 1% increase in income tax.