5 million Londoners are voting to elect new mayor . Role largely ceremonial but mayor controls 500,000 budget . Front-runners are incumbent Conservative Ken Livingstone and Olympic 's Boris Johnson . He has been found wanting by recession . Transport is key issue , especially design of city 's famous red buses .
5 million Londoners are voting to elect new mayor . Role largely ceremonial but mayor controls 500,000 budget . Front-runners are incumbent Conservative Ken Livingstone and Olympic 's Boris Johnson . Transport is key issue , especially design of city 's famous red buses .