Thousands of London bus workers have voted to go on strike in a row over extra payments for working during the Olympic Games.

Members of the Unite union backed industrial action by more than nine to one, raising the prospect of crippling walkouts during the Games, which start in the capital next month.

The union is seeking a payment of £500 for each of the 20,000 bus workers it represents in London, pointing out that other transport employees are being paid a premium for being on duty during the event.

The union will decide in the coming days whether to name strike dates following the ballot result.

Unite said it was giving the bus companies a final opportunity to consider the "landslide" ballot result before announcing possible strike dates early next week.

The union said bus workers were the only London transport employees not receiving an award for their extra effort during the Olympic Games.

At least 800,000 extra passengers are predicted to use London's buses during the Olympics, said Unite.

Regional officer Peter Kavanagh, said: "There are only seven weeks until the Olympics and the whole world is watching London. It's a disgrace that London's mayor, Boris Johnson, and the bus companies have allowed this dispute to get this far.

"Our members are only asking for an extra £17 a day which will just about buy you a pint of beer and a portion of fish and chips at the Olympics.

"Our members want the Games to be a success but their patience has run out."