Voters to decide on London mayor

The London mayor will be elected using the "supplementary vote" system

Millions of Londoners are going to the polls to end months of fierce rivalry in the fight to become London mayor.

There are 10 candidates including Labour's Ken Livingstone, Conservative Boris Johnson and Liberal Democrat Brian Paddick.

The result, which is decided by a system under which electors name their first and second choices, is not expected until Friday evening.

They will also vote for the 25 members of the London Assembly.

Polls opened at 0700 BST and close at 2200 BST.

The other candidates are Richard Barnbrook of the BNP; Gerard Batten of the UK Independence Party; Sian Berry of the Green Party; Alan Craig of Christian Choice; the Left List's Lindsey German; independent Winston McKenzie; and Matt O'Connor for the English Democrats.

Supplementary vote

Once the votes have been counted, the mayor is elected using the "supplementary vote" system.

If any candidate receives more than half of all first choice votes, he or she is automatically elected as the London mayor.

But if there is no clear winner, the two leading "first choice" candidates go through to a second round.

The candidate with the most first and second choice votes is then elected mayor.

In the event of a draw, the returning officer decides the election by drawing lots.

London has 5.5 million registered voters who can vote in the London Mayoral Election.

'Sincerely apologise'

Voters also go to the polls in the wards of Camden, Ealing, Hammersmith and Fulham and Tower Hamlets.

In Barnet, voting problems occurred when five polling stations had not received their ballot papers by the time the polls opened at 0700 BST because of overnight computer problems.

Barnet Council said as a result the automated system being used had to be checked manually.

But it said its Electoral Registration team worked throughout the night to ensure all polling stations opened on time.

"Unfortunately, a handful of polling stations did not receive their ballot papers until some minutes after 0700 BST and we sincerely apologise to those voters affected," a statement from Barnet Council said.

It said all polling stations were up and running by 0725 BST.