The ‘Westminster paedophile ring’ is a lesson in how not to carry out a police investigation

A cornerstone of any -functioning democracy is the separation of police and the courts on one hand, and government and parliament on the other. Where the latter are charged with making the law, they should never, ever be allowed to interfere with the enforcement of that law. Politicians have no power to tell the police what to investigate. As Lord Denning once observed, no policeman is subject to orders of the Secretary of State: ‘No minister of the Crown can tell him that he must, or must not, keep observation on this place or that. Or that he must prosecute this man or that one… He is answerable to the law, and to the law alone.’

In Britain, for most of the time, that separation has been respected. Prime ministers, leaders of the opposition and others with political power do not pick up the phone to Scotland Yard and demand that someone — their political opponents, for example — be investigated and prosecuted.