LONDON, May 1 (Xinhua) -- British voters are heading to the polls on Thursday in local elections across England and Wales.

    About 4,000 seats on 159 councils are up for grabs, along with the London mayor and London Assembly, the British Broadcasting Corporation reported on Thursday.

    Polls opened at 0700 BST and would close at 2200 BST. Results are expected overnight for more than 100 councils, but results from Wales, some parts of England and London wouldn't be ready until later on Friday.

    Most of the English local authorities are electing a third of the council members for a term of four years, whereas in Wales it is a complete reshuffle in the 22 unitary authorities.

    Election for the London mayor will be decided by a system under which voters name their first and second choices.

    The London city has 5.5 million registered voters and there are10 candidates for mayor, including Labor incumbent Ken Livingstone, Conservative Boris Johnson and Liberal Democrat Brian Paddick.

    The actual rivalry is in fact between Livingstone and Johnson. Polls during the campaigns have shown the two were head to head, and both are expecting better turnout to boost their support.

    Local election turnout in Britain has been decreasing over the past years, with some 37 percent for 2004.