There used to be a very useful phrase to indicate that police were apprehending wrong-doers even though they had not pressed charges.

The suspect was "helping police with their enquiries". We wonder why a number of current and former employees of banks such as Royal Bank of Scotland are not helping police in a similar way.

Last week RBS chief executive Stephen Hester announced 21 current and former employees of the bank had been disciplined or "moved on" as a result of their involvement in the Libor fixing scandal. Why are these individuals not helping police with their enquiries right now? Why has there been no attempt to apprehend these individuals for possible fraud? There is no evidence any action has been taken against the banks in Scotland.

Why has the Crown Office, which is responsible for prosecutions in Scotland, not applied the full force of the law? Royal Bank of Scotland and HBOS are Scottish-registered banks. They should be under the scrutiny of the Lord Advocate, Frank Mulholland, who decides the case for prosecution on the basis of police evidence. Scottish – and British – taxpayers have the right to expect these crimes are fully and forcefully investigated. The Crown Office has said its enquiries are ongoing but there is as yet nothing to suggest any action is pending.

The Libor fixers were involved in the manipulation of a key interest rate, on which are based literally trillions of pounds of transactions, for their own financial benefit, the benefit of the bank and the benefit of other traders and hedge funds.

This has been called the worst example of insider trading and fraud in the history of financial markets. Millions of individuals and businesses have lost money because of interest rates on their debts being increased to benefit insiders in the City of London.

The individuals who perpetrated these financial crimes must be held to account, just like any benefit fraudster or common criminal.