THE POWERS OF LOCAL GOVERNMENT
The question of whether or not a particular activity ought to be undertaken by public authority is not so simple a question in respect of local government as it is in respect of central government. If Parliament is faced with the question whether it ought to perform a given function, it has merely to balance the advantages of the proposed line of action against its disadvantages in terms of the general welfare. In a similar situation, a local agency must not only undertake such comparison; it must ask itself a question that Parliament need not ask itself. The local agency must ask itself whether it possesses the authority to do a thing that it has decided, or might decide, to be desirable. The simple reason is that all local agencies, unlike Parliament, possess only such authority as has been given to them. Moreover, they are not always completely free to exercise as they see fit all the authority that has been given to them. In other words, the problem of the function of local government is closely connected with the question of the power of local government and with the matter of control over local government.
The agencies of local government derive all their authority from Parliament. Therefore, the law that forms the source of their authority is statutory in character. On the other hand, agencies of local government must not violate the general law of the country that is applicable to them. Hence, since the Common Law is part of this general law, the Common Law, though it now seems to be recognized to be incapable of conferring authority upon local agencies, does serve to participate in fixing the legal boundaries within which local agencies operate. The boundaries of the authority of any local agency are, in other words, defined in both a positive and negative sense by law.
Local agencies, in being forbidden to violate the general law