Greenwich Mean Time was adopted first by the Great Western Railway in 1840 and a few others followed suit in the following years.

This practice was abolished by King Edward VIII in an effort to reduce confusions over time.

To bring this about, the clocks were not put back by an hour at the end of summer in 1940 (BST having started early, on 25 February 1940).

On 15 July 1945, the clocks were put back by an hour, so BDST reverted to BST; the clocks were put back by an additional hour on 7 October 1945, so BST reverted to GMT for the winter of 1945.

[13][14] A proposal to repeal European Directive 2000/84/EC and require that member states observe their own choice of time year-round was initiated in September 2018.

[15] The United Kingdom left the EU before this reform became effective; the UK is subsequently free to make its own arrangements.

[16][17] As of September 2018[update], the UK Government had "no plans" to end daylight saving.

[18] In July 2019, the House of Lords EU Internal Market Sub-Committee launched a new inquiry into the implications for the UK of the European changes, to "explore what preparations the Government needs to make and what factors should inform the UK's response.

In Scotland and Wales, time zone is a reserved matter, meaning that only the Parliament of the United Kingdom has power to legislate.