Martial law

Martial law: A code of procedure by which all the ordinary functions of police and magistrates are exercised by military authorities. Martial law must be duly proclaimed by legal processes, and when it is proclaimed the martial authorities are in supreme command of the proclaimed districts and may take any means whatever that are justifiable to secure the success of military operations, the passage of troops, the protection of a district, and the peaceable behaviour of citizens.

Under martial law offenders may be shot. The Defence of the Realm Act which was passed by Parliament since the Declaration of War constitutes a modified form of martial law, giving the military authorities ample powers to conduct military operations, but not at the same time abrogating the common-law rights of citizens.