A record £23bn (€25.9bn) in public borrowing during November is set to heap more pressure on British Chancellor Alistair Darling today.
Experts forecast official figures on borrowing will surpass the previous high of £18.9bn (€21.3bn) seen in March as the UK economy struggles through recession.
The £23bn (€25.9bn) total would be bigger than the International Monetary Fund's estimates for the entire annual output of economies such as Costa Rica and Uruguay this year.
It would also easily outstrip the £19bn (€21.4bn) borrowed by the UK for the whole of 2002.
Official forecasts published by the Chancellor in his Pre-Budget Report have raised borrowing estimates for the financial year as a whole to £178bnm (€200.6bn). Britain has borrowed £86.9bn (€97.9bn) in the seven months to October.
This reflects the impact of a far deeper-than-expected recession, although the burden would have been even worse had unemployment risen as fast as expected, while oil and share prices have performed better than had been feared.
Mr Darling plans to halve the UK's deficit within four years, with the commitment being given a legal basis by the Fiscal Responsibility Bill in November's Queen's Speech.
But he has yet to set out detailed plans for spending cuts for departments beyond protected health, education and overseas aid budgets.
Last week the Institute for Fiscal Studies (IFS) warned that the Chancellor could have to find an extra £76bn (85.65bn), or £2,400 (€2,704) per family, to restore the public finances over two parliaments of pain.
The IFS also said that debt levels could remain high "for a generation" - around 60% of national output - without policies to tackle the impact of the ageing population on the UK's public finances.