The Royal Bank of Scotland has agreed to write off half the debt owed by Huntingdon Life Sciences in order to sever its links with the laboratory.
According to a report in The Independent on Sundaythe Government brokered a deal under which the bank accepted £1 sterling in return for an outstanding £11 million overdraft.
The rest of the £22.6 million debt has been laid off to two US banks.
The banks, Allfirst, a subsidiary of Allied Irish Banks, and Comerica, have been told they will see all the cash repaid by HLS's new US backers, who have been granted anonymity by the Financial Services Authority.
Science minister Lord Sainsbury is said to have been directly involved in the secret deal.
The rescue package is understood to secure the controversial Cambridgeshire laboratory's future until 2006.
A spokesman for the Royal Bank of Scotland said: "We cannot comment on the claims made in the press because we are subject to commercial confidentiality."
PA