Union leaders today offered binding arbitration in a bid to resolve a bitter row over job losses on London Underground and avert another Tube strike next week.
The Rail Maritime and Transport union said it would accept arbitration on the use of Tube station ticket offices in advance of talks tomorrow at the conciliation service Acas.
But the union rejected as "totally meaningless" proposals for a safety review it believed would still see current staffing cuts "bulldozed through".
The union questioned LU's figures on the low number of people using some ticket offices, which the company has put forward to partly explain its plans to cut 800 jobs.
A figure of 30 ticket sales an hour to guarantee the retention of a ticket office was "wholly arbitrary", said the union.
RMT general secretary Bob Crow said: "So confident are we that the arbitrary LU figure of 30 ticket sales an hour to guarantee viability is totally bogus that we are prepared to take this issue to binding, independent arbitration.
"We also have the clearest evidence that this figure has been set up to allow the company to bulldoze through even more permanent closure of ticket office windows.
"We leaked internal documents last week which exposed LU plans to run stations unstaffed in direct contradiction of everything they have told the people of London and the 30-an-hour figure just fuels our worst fears on the company's hidden agenda.
"The proposal to conduct a station by station safety review is one that we have been calling for but to carry it out while maintaining that you will implement the planned station staffing cuts regardless, renders the whole exercise meaningless and RMT will not participate in such a farce."