In English common law there was petty treason - for example when a wife killed her husband (but not vice versa), or a servant his/her master/mistress, or a priest his superior - instances were the murderer owed particular 'faith and obedience' to their victim. Treason Act 1351
High Treason against the reigning sovereign.
Until 1814 the particular heinousness of the crime could mean the convicted traitor suffered hanging, drawing, and quartering.
Remained a capital offence until the bringing into force of the Crime and Disorder Act 1998 c 37 s 36, when replaced by life imprisonment.
Attainder meant that the punishment could extend to the next generation: heirs of traitors could be prevented from inheriting property or titles.
Treason Act 1351 (25 Edw 3 stat 5 c 2)
(a) conspiracy to kill the sovereign, his queen, or the heir apparent;
(b) violating the royal blood line
(c) fighting against the sovereign within the sovereign's kingdoms, helping his enemies
(d) the killing of certain officers of state ( Lord Chancellor, Lord High Treasurer, judges) when they are carrying out their official functions
The Treason Legislation of Henry VIII (1531-1534): Alexander Prize Essay, 1916
I. D. Thornley Transactions of the Royal Historical Society Vol. 11 (1917), pp. 87-123
Some of the subsequent legislation on treasonable offences
Treason Act 1702 (1 Anne stat 2 c 21)
Treason Act 1790 (30 Geo 3 c 48)
Treason Act 1795 (36 Geo 3 c 7)
Treason Act 1814 (54 Geo 3 c 146)
Treason Act 1842 (5 & 6 Vict c 51)
Treason Felony Act 1848 (11 & 12 Vict c 12)
Law reports with KB or AC in citation can be read online in either/both the databases below.
All ER reports are only available via LexisLibrary - in the case of Joyce below, you don't have to read both versions: the AC report is considered the more authoritative
R v Lynch  1 KB 444
R v DeJager  AC
R v Ahlers  1 KB 616
R v Casement  1 KB 98
Joyce v DPP  AC 347,  1 All ER 186
Subject searches to use in SOLO
Treason -- Great Britain -- History
Trials (Treason) -- Great Britain