The Local Government Act 1972 of England and Wales comes into effect.

The Local Government Act 1972 (c. 70) is an Act of the Parliament of the United Kingdom that reformed local government in England and Wales on 1 April 1974. It was one of the most significant Acts of Parliament to be passed by the Heath Government of 1970–74.

Its pattern of two-tier metropolitan and non-metropolitan county and district councils remains in use today in large parts of England, although the metropolitan county councils were abolished in 1986, and both county and district councils have been replaced with unitary authorities in many areas since the 1990s. In Wales, too, the Act established a similar pattern of counties and districts, but these have since been entirely replaced with a system of unitary authorities.

Elections were held to the new authorities in 1973, and they acted as "shadow authorities" until the handover date. Elections to county councils were held on 12 April, for metropolitan and Welsh districts on 10 May, and for non-metropolitan district councils on 7 June.