Not to worry though, because they say it's typical during such economic periods and besides, it's only "theoretical". That ought to make everyone feel much more at ease.
Britains biggest banks are "technically insolvent", Royal Bank of Scotland said yesterday, as the global banking industry was rocked by another day of turmoil, including the announcement of $23bn (£16bn) of new losses from Merrill Lynch and Citigroup, the giant US institutions.
Analysts working for RBS, one of several British banks to have received emergency funding from the UK Government last year, told the City that "the domestic UK banks are technically insolvent on a fully marked-to-market basis".
The warning does not mean British banks are about to go bust, because the assessment is purely theoretical, and RBS said the position was "not unusual at this stage in the economic cycle".
However, it will add to pressure on the Government to provide more support for the country's banks. Treasury officials are now set to spend this weekend in talks about a fresh round of measures, which could be unveiled as early as next week, to free up lending to households and major corporations hit by the credit crunch.
The value of Barclays fell by a quarter in stock market trading yesterday, amid a series of wild rumours about its finances, although the bank said it saw no need to comment on the drop. Its board said in a statement last night that it knew "no justification for the fall".