Voters cast their votes in a pub being used as a polling station in west London, Britain May 5, 2016. [Photo/Agencies]

LONDON - Millions of people are voting across Britain in what is being called Super Thursday. When the first results start to flow in some time after midnight, it will give the earliest indications on whether the political landscape is likely to change in the country.

Thursday's elections are the first big test for main opposition leader Jeremy Corbyn since his election last year as leader of the Labour Party.

Elections are taking place for the Scottish Parliament, the National Assembly for Wales and the Northern Ireland Assembly, as well as for directly elected mayors in London and several other cities.

Directly-elected police and crime commissioners are also up for election on Thursday in England and Wales, as well as councilors in around 140 towns and cities. Two House of Commons seats are also being contested.

London will be seen as a focal point for political watchers and commentators with Conservative Boris Johnson's eight-year rule coming to an end.

The battle for London is likely to be between Conservative Zac Goldsmith and Labour's Sadiq Khan. There are 10 other candidates in the race for London, but the latest polls has given Labour the lead.

Londoners will also be voting Thursday for members to serve on the London Assembly, the 25-strong body that keeps a watch on the mayor. Currently the assembly is made up of 12 Labour, nine Conservatives, two Greens and two Liberal Democrats members.

In Scotland, the Scottish National Party (SNP) is in control with a single-digit majority over the combined opposition benches at Holyrood. In 2011 it won 69 seats, followed by Labour with 37, Conservatives with 15 and the Liberal Democrats 8.

The power base in Wales is finely balanced, with Labour as the largest party holding 30 of the 60 seats in the Cardiff assembly. The Conservatives have 14 seats, Plaid Cymru 11 and the Liberal Democrats 5. Nigel Farage's UK Independence Party (UKIP) is predicting it will win its first seats in the assembly.

More than 270 candidates are competing for the 108 seats in the Northern Ireland Assembly.