A union planning industrial action by London bus workers over an Olympic payment has stepped up pressure by saying its claim for extra pay will increase if strikes go ahead.
Members of Unite are planning a 24-hour walkout on Friday over a claim for £500 for working during the Games.
The union said it will add a day's pay to its claim if the strike goes ahead.
Unite's regional secretary for London, Peter Kavanagh, said: "Bus workers will be on the front line of London's transport network during the Olympics but they have been treated with contempt by the bus companies and Transport for London (TfL).
"They are claiming an award which every other London transport worker will receive. If bus workers are forced to take strike action, we will increase our claim of £500.
"TfL and the bus companies cannot just think they can do nothing and see strike action out. They have to stop burying their heads in the sand and treat bus workers fairly or face damaging strike action and the prospect of a day's pay being added to the claim."
More than 20,000 members of Unite working for 21 London bus operators, including Go Ahead, Stagecoach, London United, Arriva, Metroline, First and Abellio backed strike action by an average of 94%.
The Rail, Maritime and Transport union warned of a "massive impact" on Tube and rail services on Friday as millions of passengers try to find alternative means of travel as a result of the bus workers strike.
Leon Daniels, TfL's managing director of surface transport, said: "This remains an issue between the private bus operating companies and the bus workers they employ.
"While everyone responsible is working flat out to deliver a successful 2012 Games, the latest threat from Unite clearly demonstrates their continuing attempts to hold the capital's travelling public to ransom. It is extraordinary that Unite now wants the capital's taxpayers and farepayers to fund its members' strike action as well."