Governor's pointed remarks
Asked about budget policy, Mervyn King will usually politely refer inquiries to HM Treasury. After all, the independence of the Bank of England is a two-way street. Since he doesn't want ministers weighing in on monetary policy, he has usually shown them the courtesy of resisting commentary on the budget.
There have been exceptions. But none as pointed as his remarks to the Treasury Select Committee this morning, where he effectively said that the government would be mad to consider another large stimulus package.
Why change the habits of a decade? And why now - with Budget Day less than a month away?
There are two possible explanations. One is that he thinks the British budget is now in such a bad way that saying this is no longer controversial.
The other is that the governor wants to give public support to those in the government - notably in the Treasury - who are resisting calls for another fiscal stimulus on 22 April.
I suspect both are true. As I flagged up last week, the IMF now thinks the UK will have a deficit of 11% of GDP in 2010, compared with a G20 average of 6.3%. The Item Club has since produced its own forecast for a deficit of more than 13% in 2010-11.
The fund's figures also showed that we have had the largest swing into the red since 2007 of any major G20 economy. Our borrowing will have risen by 6% of GDP per year, on average, between 2007 and 2010.
"Given how big these deficits are", King said this morning, "I think it would be sensible to be cautious about going further in using discretionary measures to expand the size of the those deficits."
Many economists would consider that a simple statement of fact. When you are in a cavernous hole you think long and hard before digging a lot more, especially when you're a country hugely dependent on selling its government debt to foreigners.
Given the risks to the budget of failing to prevent a depression, there may come a time when the government has to contemplate another stimulus package. But anyone would say you'd need to tread cautiously.
Yet, clearly, Mervyn King is not just another City economist. He will have been well aware that this was consequential, especially with debates over fiscal stimulus likely to be front and centre at next week's G20 Summit.
And he didn't leave it there. He went on: "that's not to rule out targeted and selected measures... But I think the fiscal position in the UK is not one where we could say, well, why don't we just engage in another significant round of fiscal expansion?"
This is more words on fiscal policy than the governor has uttered in a long time. At a time when the Treasury is fighting to prevent another big stimulus going into the Budget, it is difficult to escape the conclusion that Mervyn King wanted everyone to know exactly which side he was on.
Even the fiscal activists at No 10 are not contemplating a US-style fiscal package. And as the IFS has noted repeatedly, last year's stimulus was itself a pretty feeble affair. The vast bulk of the rise in UK borrowing is due to things beyond the government's control, particularly the impact of the recession on revenues.
King is not saying the government should seek to prevent the automatic stabilisers from operating. High and rising deficits are inevitable for at least a couple of years. Though George Osborne has suggested otherwise, nor is he asserting that the earlier fiscal stimulus was a mistake.
The governor's remarks today are consistent with what he said on that subject at the November inflation report press conference. At that time he said a fiscal stimulus would be a "perfectly reasonable" response to the crisis, provided that it would it be "temporary, purely temporary", and "that it would be clear that there was a medium term plan to bring tax and spending back into a sustainable balance over the medium term."
You could say that today's comments are merely an updated version of this view. You could also, as I said at the start, say that they were a pretty uncontroversial description of Britain's fiscal position. But if there are senior members of the government who think a big second stimulus is a live issue, they've been put on notice that the governor doesn't agree.