Thousands of London bus workers will go on strike next Friday in a row over extra pay for working during the Olympics.
Unite said buses in the capital will come to a standstill as bus workers from every London bus operator will walk out for the first time in a generation.
The strike is over Unite's claim for a £500 bonus for over 20,000 workers to recognise the "massive increase" in workload during the Games.
Unite said that unless the bus operators make an offer, the union will call further strikes up to and during the Olympic Games.
The last London wide bus strike took place in 1982.
Unite's regional secretary for London, Peter Kavanagh, said: "London buses will come to a standstill for the first time in a generation across London on 22 June.
"The blame lies squarely with the bus operators and Transport for London. The bus companies haven't met with Unite once to discuss bus workers' extra contribution to the Olympic games and TfL has refused to intervene.
"This dispute could be resolved at a stroke but if the bus companies and TfL continue to do nothing Unite will call further strikes up to and during the Olympic Games.
"Bus workers are on the frontline of London's transport system dealing with millions of passengers yet all TfL has done so far is insult them."
Unite said bus workers were the only London transport workers not receiving an award for their extra effort during the Olympics.
Deals have been announced giving workers at Heathrow Express £700, Network Rail £500, Docklands Light Railway £900, Virgin Rail £500, London Overground £600 and London Underground at least £850, said Unite.