The Bank of England has revealed for the first time that it lent the Royal Bank of Scotland and Halifax Bank of Scotland £61.6 billion ($NZ1325 billion) in emergency funding.
Bank governor Mervyn King told a committee of MPs the loans were made last October to prevent a loss of confidence spreading through the financial system as a whole, the BBC reports.
The money was repaid in full by January.
The Bank says it was fearful the information would have damaging consequences if revealed last year, so it kept it secret until now.
British Chancellor Alistair Darling had agreed to underwrite any losses which the Bank may have made on the loans.