Talks between the RMT union and London Underground over Olympic bonus payments for tube staff have broken down.
The negotiations at the Acas conciliation service ended when London Underground imposed a series of new conditions.
An RMT spokesperson said bosses were trying “to force staff to work in
safety-critical roles in unfamiliar locations that they are not properly trained for”.
Acas talks between London Underground and the Unite union on Olympics payments also broke down earlier this month.
Unite is also balloting 28,000 bus drivers on Friday of this week over the refusal of London bus companies to discuss Olympic payments.