Railway electrification in Great Britain started in the late 19th century. After World War II and the nationalisation of the railways in 1948 and the 1955 Modernisation Plan, electrification commenced in earnest. After a pause, the West Coast Main Line north of Weaver Junction to just south of Glasgow was electrified between 1970 and 1974. Small amounts of the rail system then followed, with more electrification occurring in the 1980s, including the East Coast Main Line.
From the mid-1990s to late 2000s, electrification of the network stalled. In 2009, Lord Adonis was appointed Secretary of State for Transport. After a gap of more than a decade, electrification was back on the agenda and Adonis announced plans to electrify the Great Western Main Line from London as far as Swansea, as well as infill electrification schemes in the North West of England. In July 2012 the UK coalition government announced new electrification schemes, all at 25 kV AC, and reconfirmed schemes previously announced by Adonis. Devolved rail transport in Scotland has allowed the Scottish government to pursue electrification with multiple schemes in the Central Belt. This has been followed up by a further commitment to a low carbon economy and a modal shift to enable it. The 2009 government document was refreshed in January 2015.
However, electrification has not been without controversy, with cost overruns and late-running schemes, particularly on the Great Western Main Line. This led to cancellations of projects and various appearances of the Secretary of State for Transport called before the Transport Select Committee. Shortly after this, Campaign to Electrify Britain's Railway was launched to try and mitigate the boom and bust cycle.