Rail union RMT has revealed that there will be further strike action on South Western Railway on 22 December, the final Saturday before Christmas.
The National Union of Rail, Maritime and Transport Workers have said that the decision has come as a result of South Western's refusal to engage in serious discussions regarding the long-running guards' safety dispute.
Commercial guards, guards, and train drivers have been instructed not to book any shifts that commence during a 24-hour period on that day.
It coincides with a Central Line strike on 21 and 22 December that RMT has already announced.
RMT general secretary Mick Cash said: “South Western Railway continues to refuse to make any progress at all in resolving this dispute, which is about safety, security and access on South Western Railway. The company are hell bent on opening up a loophole that would allow them to run services driver only at their discretion.
“Recent figures have shown a shocking surge in violence on our railways across the festive season and it is frankly appalling that South Western Railway are looking for a green light to throw the guard off their trains as and when they see fit in the name of profit.
"SWR might think it’s acceptable to play fast and loose with passenger safety, security and access but RMT members, who have stood firm throughout this dispute despite appalling harassment from the company, will not accept a dilution of the safety regime on the railway."
The union was also responsible for disruption in November when members went on strike on both Southern and Northern railways two weeks ago.
They were also behind the recent Central Line strikes.
South Western Railway did not immediately respond to a request for comment.