Royal Bank of Scotland has been chosen to provide advice to police on financial crime just days after its own bill to settle regulatory investigations into past misconduct topped more than £1 billion.
RBS, which is 80% owned by the taxpayer, is to provide volunteers to help the City of London Police with training and research - in a move that has raised eyebrows in the light of the lender's controversial recent history.
Tory MP Guto Bebb, member of the Commons Public Accounts Committee, told the Huffington Post UK: “It is difficult to comprehend the thinking behind the decision of the City Police to invite RBS to advise them on financial crime. Then again, poachers turned gamekeepers does come to mind."
Rescued during the financial crisis with a £46 billion taxpayer bailout that remains outstanding, RBS last week set aside £400 million to settle claims of foreign exchange (forex) market rigging.
It is facing probes by the UK's Financial Conduct Authority and Serious Fraud Office, as well as America's Department of Justice and other US bodies over the forex claims.
The bank has previously paid more than £700 million in fines to global regulators for rigging benchmark interbank lending rates such as Libor. RBS's bill for compensating customers mis-sold payment protection insurance has reached £3.3 billion.
The City force, which is national policing lead for fraud, handles some of the UK's most high profile economic crimes.
It said that while its officers were already highly-trained specialists, it could benefit from banks "in areas such as equities and markets, financial instruments, international jurisdictions, cyber technology and foreign languages".
But the RBS staff will not be involved in any operational police activity or be asked to advise on information relating to specific investigations.
Commissioner Adrian Leppard said he hoped it would be the first of many such agreements with the financial sector.
"We can now tap into their massive knowledge base of financial products and digital technology and use their foreign language
skills, which reflects the increasingly international dimension of economic crime investigation."
Emma Smith, head of security, resilience and control at RBS, said: "I am delighted to have signed this agreement and look forward to working closely with the City of London Police in their fight against financial crime.
"The experience and expertise of our employees will help safeguard our customers and others."