Workers on South Western Railway are to strike for 27 days before the end of the year in the long-running dispute over guards on trains.
Members of the Rail, Maritime and Transport union will walk out for 27 days between December 2 and New Year's Day, threatening travel chaos for commuters and Christmas shoppers.
RMT general secretary Mick Cash said: "Our members have been left with no choice but to call a further 27 days of strike action on South Western Railway."
Steve Hedley, Assistant General Secretary-RMT
A South Western Railway spokesperson said: “We are extremely disappointed that the RMT union has once again called for their members to take disruptive industrial action. The deliberate targeting of services up to, and during, the Christmas period is typical of the lack of concern the RMT continue to have for our customers."