Prosecutions for insider dealing and market abuse have been notoriously thin on the ground. Margaret Cole, the Financial Services Authority’s (FSA’s) director of enforcement, told the Treasury Select Committee last month that one of the major reasons US authorities have been more successful in prosecuting in this area is because they have more tools to build the evidence to bring cases, including the ability to enter into immunity arrangements with cooperating witnesses.

Last March the Chancellor of the Exchequer, Alistair Darling, stated that he would give the FSA the power to do just that. Under the proposals, the FSA would gain “specified prosecutor status”. As such, prosecutors from the FSA would join the list of people permitted to grant immunity from prosecution under section 71 of the Serious Organised Crime and Police Act 2005 (SOCPA). Currently, this list includes the director of public prosecutions, the director of revenue and customs prosecutions and the director of the Serious Fraud Office, as well as those designated as specified prosecutors by those individuals. Section 71 states that if a specified prosecutor thinks that for the purposes of the investigation it is appropriate to offer a person immunity, they might give the person a written notice, known as an “immunity notice”. Once such a notice is given, no proceedings for an offence of the description specified in the notice may be brought in England and Wales or Northern Ireland.