London - British Prime Minister Gordon Brown is facing his first electoral test since he came to power last June in local elections in large parts of England and in Wales Thursday.

Up to 60 per cent of the national electorate of about 40 million are called upon to choose councillors in towns and cities across the country, while Londoners will vote in a mayoral election.

The elections are seen as having national importance, as Brown's Labour Party could face setbacks following a string of unfavourable opinion polls.

They show that the Conservatives, under David Cameron, are up to 20 points ahead of Labour, and that voters are dissatisfied with Brown's leadership.

However, all eyes will be on London where Mayor Ken Livingstone is facing a strong challenge from Conservative candidate, Boris Johnson.

A defeat in London would be seen as a serious blow to the Labour Party, and by implication, to Brown.

Livingstone, the maverick mayor best known for introducing a charge to ease traffic congestion, has ruled London since 2000. (dpa)