Numbered year running from the date of a monarch’s accession.

In citing legislation, particularly for older statutes, the regnal year of the monarch who gave the royal assent to the Act is included, as well as a chapter number.

Before the Short Titles Act 1896 statutes were commonly known by regnal year and chapter number alone. The 1896 Act conferred short titles on most statutes still in force at that date which did not already have one.

So for example, the Treason Act 1351 is the short title of what was originally called the “Declaration what Offences shall be adjudged Treason” and as the second chapter in the fifth statute made in the 25th year King Edward III, should be cited (25 Edw 3, stat 5, c 2).

Since 1896 all statutes have had short titles, eg Human Tissue Act 1961 (9 & 10 Eliz 2, c 54).

Since the Acts of Parliament Numbering and Citation Act 1962 (10 & 11 Eliz 2, c 34) chapter numbers have been assigned by reference to the calendar year, not the regnal year of the parliamentary session in which they have been passed. For any Act passed in or after 1963, it is no longer necessary to give the regnal year as part of the chapter citation.