On the eve of its first strike over the imposition of rosters the union believes will leave stations dangerously understaffed, RMT called on LUL and the Mayor to respond positively to its compromise offer that would enable the Tube to run and talks to take place.

"Our offer to suspend strike action if Tube bosses suspend the imposition of the new rosters at the heart of this dispute remains on the table, but time is running out," RMT general secretary Bob Crow said today.

"Rather than accept our olive branch LUL yesterday repeated the myth that we are seeking to renegotiate the 35-hour week deal, and unfortunately the Mayor has joined in.

"For the record, we do not want to renegotiate the deal, but want LUL to stick to the one we actually signed.

"The rosters LUL want to impose were not a part of that deal, and the number of staff being displaced could be more than four times the 200 we were given to believe would be the case.

"The effect of these imposed rosters will be to reduce the number of station staff on duty at any one time, in many cases by more than half, and that is the crux of this dispute.

"That casts doubt on our ability to respond adequately to emergencies of all sorts, and therefore poses an unacceptable threat to safety, both for our members and for Tube users.

"Maybe the Mayor is not aware of the shabby strokes his Tube bosses have pulled since we signed that deal, but he will recall that, as a Mayoral candidate courting our support, he once pledged to stand shoulder-to-shoulder with RMT members on the picket line.

"He should reflect that our members, people who deliver a public service every day of the year, have voted by a margin of five to one to defend Tube safety, not just for themselves but for everyone who uses the network," Bob Crow said.