Vote-counting taking place across Britain

Britain's Prime Minister David Cameron and his wife Samantha leave the polling station after casting their votes in Westminster, central London, Thursday May 5, 2016. Britons are voting in local and regional elections expected to deal a blow to Britain's main opposition Labour Party. (Philip Toscano-Heighton/PA via AP) UNITED KINGDOM OUT (The Associated Press)

Britain's Labour party leader Jeremy Corbyn arrives to cast his vote at a polling station in Islington, north London Thursday May 5, 2016. Britons voted Thursday in local and regional elections that will choose a new mayor for London — and are expected to deal a blow to Britain's main opposition Labour Party. Voters are electing a Scottish Parliament, legislatures in Wales and Northern Ireland as well as choosing many English local authorities, including a new London mayor to replace flamboyant Conservative Boris Johnson. (Stefan Rousseau/PA via AP) UNITED KINGDOM OUT (The Associated Press)

Counting staff at the ExCel Centre in east London sort through ballot papers cast Thursday in the elections of the London Mayor and the London Assembly Friday May 6, 2016. The result in the London Mayoral election is expected Friday evening. (Stefan Rousseau/PA via AP) UNITED KINGDOM OUT (The Associated Press)

Votes are being counted throughout Britain to determine London's new mayor, control of many city councils, and national assemblies in Northern Ireland and Wales.

In Scotland, the pro-independence Scottish National Party scored well to keep control of the Scottish Parliament by a wide margin.

In the English city of Liverpool, Labour's Joe Anderson held on as mayor. The mayoral race in London pits Labour's Sadiq Khan and Conservative Zac Goldsmith, with results expected late Friday.

The series of elections is seen as a first test of Labour leader Jeremy Corbyn's ability to unify the party, which has been unsettled by charges of anti-Semitism in its ranks. Some commentators and polls had predicted the party would suffer a drubbing, but early results appeared more positive for Labour.