ABSTRACT

Although the British constitution is unwritten and not therefore embodied in any one document, it is usually possible to define some aspect of the British constitutional framework from the existing law, difficult though that may be. In the previous section on the Rule of Law reference was made to police powers of arrest. Where it is necessary to ascertain the scope of police powers to enter and question a person on his own property such an issue has probably arisen from that person’s refusal to be questioned in such circumstances. If as a result he is arrested for the obstruction of a police officer in the execution of his duty, contrary to s 51 of the Police Act 1964, his conviction will depend on whether there was an obstruction and whether the officer was acting in the execution of his duty. Because these terms are not defined by the Act, their definition has been left to the courts; that is, they are terms of art developed through the common law. Consequently, this area of the constitution regulating powers of the police can be defined only by reference to statute and common law, that is, a combination of Act of Parliament and case law. Accordingly, it is likely that a court would conclude that there could be no conviction for obstruction under s 51 where the police officer is told to leave the person’s property because, as a trespasser, he would not have been acting in the execution of his duty. There can be no doubt that the Rule of Law requiring government according to law is fundamental to the constitutional background of administrative law. There are, however, other facets of the constitutional structure which must be examined in order to appreciate the true significance of the law’s ability to control government powers. These other facets include the sovereignty and supremacy of Parliament, the separation of powers, conventions and prerogative powers.