For other uses see High treason (disambiguation).
See main article: Treason and High treason in the United Kingdom. High treason is criminal disloyalty to one's country. Participating in a war against one's country, attempting to overthrow its government, spying on its military, its diplomats, or its secret services for a hostile and foreign power, or attempting to kill its head of state are perhaps the best-known examples of high treason. High treason requires that the alleged traitor have obligations of loyalty in the state they betrayed, such as citizenship, although presence in the state at the time is sufficient. Foreign spies, assassins, and saboteurs, though not suffering the dishonor associated with conviction for high treason, may still be tried and punished judicially for acts of espionage, assassination, or sabotage, though in contemporary times, foreign spies and saboteurs are usually repatriated following capture.
Historically, in common law countries high treason was differentiated from petty treason, which was the act of killing a lawful superior (such as a servant killing his or her master or mistress). It was, in effect, considered a more serious degree of murder. As jurisdictions around the world abolished petty treason, the concept of petty treason gradually faded, and today use of the word "treason" generally refers to "high treason."
In Canadian law however, there are two separate offences of treason and high treason, but both of these, in fact, fall in the historical category of high treason. In Canada, the main difference in law between treason and high treason is contingent on whether the nation is at war or not. The spectrum of acts (attempting to overthrow the government, spying for a foreign power, revealing state/military secrets, etc.) generally considered de facto treasonous are considered in peacetime to constitute the crime of “treason”. The same acts, committed in wartime, however, constitute the crime of “high treason”. Only the act of attempting to assassinate the Head of State (the regnant monarch) is legally considered “high treason” during times of peace. The practical distinction between the two offenses is, however, minimal. The punishment for high treason in Canadian law is life imprisonment and the punishment for treason is the same, excepting where the treasonous offence is the betrayal of scientific or military state secrets. The punishment in this situation is life imprisonment during wartime (high treason), but imprisonment of a term not exceeding fourteen years duration in peacetime (treason).