|Long title||Declaration what Offences shall be adjudged Treason.[b]|
|Citation||25 Edw 3 St 5 c 2|
|Revised text of statute as amended|
The Treason Act 1351 is an Act of the Parliament of England which codified and curtailed the common law offence of treason. No new offences were created by the statute. It is one of the earliest English statutes still in force, although it has been very significantly amended. It was extended to Ireland in 1495 and to Scotland in 1708. The Act was passed at Westminster in the Hilary term of 1351, in the 25th year of the reign of Edward III and was entitled "A Declaration which Offences shall be adjudged Treason". It was passed to clarify precisely what was treason, as the definition under common law had been expanded rapidly by the courts until its scope was controversially wide. The Act was last used to prosecute William Joyce in 1945 for collaborating with Germany in World War II.
The Act is still in force in the United Kingdom. It is also still in force in some former British colonies, including New South Wales. Like other laws of the time, it was written in Norman French.
The Act is the origin of the definition of treason in the United States (in Article III of the Constitution). Joseph Story wrote in his Commentaries on the Constitution of the United States that:
they have adopted the very words of the Statute of Treason of Edward the Third; and thus by implication, in order to cut off at once all chances of arbitrary constructions, they have recognized the well-settled interpretation of these phrases in the administration of criminal law, which has prevailed for ages.
Until 1351 treason was defined by the common law. The king's judges gradually expanded the scope of treason under the pretext that any "assortment of royal power," by which was meant doing anything which only the king (or his officers) could legally do, was considered treason - even hunting deer in the king's forests.:307 When a John Gerberge of Royston was convicted of treason for falsely imprisoning someone who owed him £90, the barons compelled Edward III to agree to an Act of Parliament to restrict the definition of treason to definite limits.:307
The Act distinguished two varieties of treason: high treason and petty treason (or petit treason), the first being disloyalty to the Sovereign, and the second being disloyalty to a subject. The practical distinction was the consequence of being convicted: for a high treason, the penalty was death by hanging, drawing and quartering (for a man) or drawing and burning (for a woman), and the traitor's property would escheat to the Crown; in the case of a petty treason the penalty was drawing and hanging without quartering, or burning without drawing; and property escheated only to the traitor's immediate lord.
A person was guilty of high treason under the Act if they:
Under the Act petty treason was the murder of one's lawful superior: that is if a servant killed his master or his master's wife, a wife killed her husband or a clergyman killed his prelate. This offence was abolished in 1828.
The Act originally envisaged that further forms of treason would arise that would not be covered by the Act, so it legislated for this possibility. The words from "Et si per cas" onwards have been translated as:
And because that many other like Cases of Treason may happen in Time to come, which a Man cannot think nor declare at this present Time; it is accorded, That if any other Case, supposed Treason, which is not above specified, doth happen before any Justices, the Justices shall tarry without any going to Judgement of the Treason till the Cause be shewed and declared before the King and his Parliament, whether it ought to be judged Treason or other Felony.
Following the union of England and Scotland by the Acts of Union 1707, Scotland continued to have its own treason laws until the Treason Act 1708 abolished Scottish treason law and extended English treason law to Scotland. This Act also made it treason to counterfeit the Great Seal of Scotland, and to kill the Scottish Lords of Session and Lords of Justiciary (in addition to forging the British - formerly English - seal, and killing English judges). However while in England and Ireland forgery of the seal of Great Britain ceased to be treason under the Forgery Act 1861, this Act did not apply to Scotland. Also, forging the Scottish seal is still treason in Scotland, but has not been treason in England or Ireland since 1861.
Although the first kind of treason is described as "compassing," the offence does not consist of purely thinking. A subsequent clause which requires that an "overt act" must also be proven has been held by judges to apply to all kinds of treason.:308
Adhering to "enemies" does not include adhering to rebels or pirates.:308
During the trial of Roger Casement, who in 1916 was accused of collaborating with Germany during World War I, the defence argued that the Act applied only to activities carried out on British soil, while Casement had committed the acts of collaboration outside Britain. However, closer reading of the originally unpunctuated medieval document allowed for a broader interpretation, leading to the accusation by his supporters that Casement was "hanged by a comma". The court decided that a comma should be read in the text, crucially widening the sense so that "in the realm or elsewhere" meant where acts were done and not just where the "King's enemies" might be.
The clauses about forgery and counterfeiting were repealed in 1830 and 1832. The words from "Et si per cas" onwards were repealed by the Criminal Law Act 1967 and the Criminal Law Act (Northern Ireland) 1967.