A war of words is raging after two-thirds of bus services in London were cancelled because of a strike by thousands of workers in a dispute over an Olympic bonus.
Unite said support for the 24-hour stoppage among its members at 17 bus companies was solid, with picket lines mounted outside depots across the capital, as it warned that further strikes would be bigger.
London Mayor Boris Johnson said it was "disgraceful" that a financial package of £8.3 million he brokered for bus workers to have an Olympic bonus was not put to union members.
Talks between Unite, which is seeking a £500 bonus for workers, and bus companies ended without agreement at the conciliation service Acas, with no sign of an early resumption.
The Mayor said: "It is disgraceful that the financial package we have brokered, offering extra cash for bus drivers, has not even been put to members. This is an absolute dereliction of duty by union leaders and as a result, some Londoners have faced unnecessary disruption.
"Many Londoners, who today defied the strike, will be working hard during the Games with no extra pay. They will believe this offer is more than fair and find it difficult to understand why this strike action could not have been postponed.
"Militant union leaders have not succeeded in their aim to bring London to a standstill. I thank those drivers who have so far turned out, enabling us to run a third of services across the morning period.
"I feel sorry for those drivers currently sitting at home wondering whether to come in for their shifts, and who face losing a day's pay for striking, yet still don't know what was offered to them. I hope more of them choose to come into work, recognising the offer made to resolve this dispute."
Unite vowed to appeal against a High Court injunction granted to three bus companies, preventing its members there from joining the walkout.
London regional secretary Peter Kavanagh said: "Support for today's strike action is solid and shows that bus workers are willing to stand shoulder to shoulder to get the recognition they deserve in keeping London moving during the Olympics.
"Today's strike comes as bus operators hide behind an anti-democratic court injunction and refuse to settle the dispute. We will fight to get the injunction overturned and further action will be bigger if Transport for London and the bus operators continue to bury their head in the sand.
"The strike should be a wake-up call to the bus companies and TfL. They now need to negotiate meaningfully about rewarding bus workers for the massive increase in workload they will face over the Olympics."
Transport commissioner Peter Hendy said: "It is now clear that the leadership of Unite were intent on a strike all along. They have pursued this unnecessary course of action despite an extra £8.3 million being brokered by the mayor that would allow every bus driver in London in a garage where one or more routes were affected by the 2012 Games to gain, over the 29 days of the competitions, about £500.
"Despite additional offers to supplement this from the bus companies, the Unite leadership have refused to defer the strike to give time for further negotiations or for any of the offers to be put to their members. I'm sorry that Londoners are therefore going to be disrupted today."
The strike will continue until 3am on Saturday.