A state of emergency is a declaration that empowers a government to pass through policies it otherwise would not be allowed to do for the safety and protection of citizens. It can be declared before, during or after a natural disaster, civil unrest, armed conflict, medical pandemic or other biosecurity risk. During a state of emergency, the government can confiscate private property, impose travel restrictions, commandeer or ration certain infrastructure like broadcasting and utilities and generally instruct or require privately owned businesses to help with relief efforts.
Most states have statutes that allow the governor to declare a state of emergency in response to a variety of situations, including natural disasters, terrorism and events that threaten public health. These provisions have been abused by dictators to circumvent democratic processes and to override human rights of their citizens usually protected by the International Covenant on Civil and Political Rights.
The state of emergency can last for 30 days, or until revoked by Parliament. The British monarch, on the advice of the Privy Council, has the power to introduce emergency regulations in response to a terrorist attack or an event that threatens public security and national security in all places within the UK. This power was used during the 1974 Black Power Revolution and again in October 1970 to respond to industrial action. It may be revoked by the Queen or the Prime Minister on their own or jointly with Parliament.