With the news that a police woman in Northumberland has been arrested for misconduct in a public office for being involved in prostitution it is a good time to consider where this offence comes from in the first place.

Its origins are in the common law and it was, until recently, rarely used. It was first described by Lord Mansfield in 1783 in relation to the misuse of offices under the crown, particularly where there was an element of profit. It has applied to JP's and very many of the times when prosecutions mainly involved Police Officers neglecting their duties or, more frequently, where they had been corrupt.

It was only in about 1997 that the offence was resurrected with any frequency. This was because it was thought for a while that Police Officers who were misusing the Police National Computer could not be prosecuted for the modern offence of "computer misuse" because they were thought to have been entitled to use the computer for legitimate reasons. The offence of misuse of public office was resurrected to get around this and so came back into the minds of prosecuting lawyers. Surprisingly there are "fashions" in the use of laws and a tendency to stretch a law as far as it can go. That is surely what has now happened with this offence. A police officer working as a prostitute may be undesirable but it is not unlawful and surely has nothing to do with her job. As has now repeatedly been pointed out the leaking and the receiving of leaks of material that did not involve national security was expressly supposed to be excluded from prosecution under the Official Secrets Act. Frustrated by this it seems that the "authorities" in the shape of the government, the Crown Prosecution Service and the Police have now proceeded to use it to suppress both the press and now Parliament.

There is the clearest link, in the shape of this offence, between the arrest of Damian Green and the unsuccessful prosecution of Sally Murrer. One was an attempt to silence or punish the press arising from a police officer making a fuss over the bugging of inmates in Woodhill prison. It is easy to see what has happened to Damian Green as an attempt, in the run up to the next election, to frighten civil servants as to the consequences of leaking, so reducing the ammunition available to the opposition. If it does no more than silence the apparent mole in the Treasury it will presumably have served its purpose.