So the government has been put on notice to reduce public sector debt by one of the agencies widely regarded as having exaggerated the safety and quality of all manner of investment products that turned out to be toxic.
However the right response is not to laugh.
Standard & Poor's, like Moody's and Fitch, still has tremendous clout - not least because even the Bank of England still uses their ratings of creditworthiness to determine which assets and securities it will take from banks.
First things first. No reason to panic.
There may have been a bit of weakness in sterling and UK government bonds or gilts this morning. But nothing cataclysmic.
And, strikingly, the Debt Management Office has this morning completed the biggest ever auction of gilts in history. And it sold the lot very comfortably indeed, with far more bids than it needed.
So we ain't bust yet.
Also, S&P has not said that the UK will definitely lose its triple-A rating, its rare and precious badge that we are good for our IOU's in all seasons.
Putting British sovereign debt on negative outlook is not as bad as being assessed for possible downgrade, which almost always leads to a downgrade.
Apparently, a negative outlook is followed by downgrade in about a third of cases.
And some would say that S&P is stating the bloomin' obvious, that public sector debt is patently rising too fast - and that we can't assess the long term health of the economy, or the ability of the government to meet its financial obligations, till we know the taxation and debt plans of the next government.
S&P is thus in slightly different language repeating what the IMF said yesterday, that the UK needs a bolder plan to stem the rise in the national debt.