Yesterday the UK government tried to raise £1.75bn to cover current expenditure by selling 40-year bonds (gilts) and failed. Buyers took £1.63bn and left a shortfall of £120 million.
Since the shortfall amounts to about half-an-hour's spending by our prodigal government this isn't too dramatic so far.
The question is: is this a one-off or is UK debt no-longer sellable? If the latter then we've got big problems.
There are plenty of things the government can do at the moment to fix the problem. They could sell shorter term debt, eg 10yr bonds; generally the shorter the term the less risk the buyer is taking and so the more acceptable the offering. Or they could raise interest rates. That would be a good thing to do since Tuesday's numbers show that the inflation monster has risen from its coffin and is once again sucking blood from the economy. The Bank of England will be setting a new base rate in a couple of weeks (on the 9th April) so that's their opportunity.
And if none of that works, there's always the IMF.