A spent law or spent enactment is a piece of legislation which is still in force, but which could be repealed without any practical consequences.
The repeal of spent legislation is primarily the responsibility of the Law Commission. They prepare Bills to be passed as Statute Law (Repeals) Acts.
The following types of enactment are now spent on coming into force:
Enactments conferring short titles
Section 19(2) of the Interpretation Act 1978 provides that an Act may continue to be cited by the short title authorised by any enactment notwithstanding the repeal of that enactment. This applies to Acts whenever they were passed.[1]
Accordingly any enactment whose sole effect is to confer a short title on an Act now becomes spent on coming into force; and any enactment already in force whose sole effect is to confer a short title on an Act is also spent.
Those enactments which conferred short titles on large numbers of statutes have been repealed on this basis.[2][3]
Enactments which repeal other enactments
Section 15 of the Interpretation Act 1978 provides that where an Act repeals a repealing enactment, the repeal does not revive any enactment previously repealed unless words are added reviving it. This applies to Acts passed after the year 1850.[4]
Accordingly, any enactment whose sole effect is to repeal another enactment now becomes spent on coming into force; and any enactment, which is already in force, whose sole effect is to repeal another enactment is also spent.