"Escalated strike action will be called from Monday 6th February unless London Underground meet RMT’s reasonable demands on station staffing and safety," the union’s statement read.
Tube management conceded that 838 jobs, cut by the previous London mayor, had left station control rooms understaffed, creating a "devastating impact" on passenger safety, RMT said.
The union stressed next month’s deadline gave transport authorities ample time to come forward with serious proposals as a basis for further negotiation.
Tube employees continued industrial action this week after failed negotiations between transport and union bosses led to a 24-hour strike on Sunday through Monday, stranding commuters and crippling public traffic.
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