The RMT has changed the dates of its Southern Rail strike, moving a Christmas eve walkout to earlier in the week.
Union members are embroiled in a long-standing, bitter dispute with Southern over changes to the roles of train guards, and have already launched a series of debilitating strikes.
They were due to stage a three-day walkout from December 22, which would have included Christmas eve, but this has now been changed to a 48-hour strike starting from the 19th.
The RMT said the move followed consultation with its members who were affected by the dispute, as well as with passengers.
Other strikes the union has called remain in force. These are happening from December 6 to 8, and from New Year’s Eve to January 2.
RMT general secretary Mick Cash said: ‘Our guards on Southern are in daily contact with passengers and the support for our fight to defend safety remains phenomenal.
‘RMT is truly grateful for the overwhelming public backing for the campaign to keep a second, safety-critical member of staff on Southern trains.
‘It is from that daily feedback from passengers that the union has taken the decision to alter the dates for action over Christmas. That’s the difference between us and Southern. We listen, they don’t.’
Southern will be further crippled by separate strikes launched by Aslef, whose general secretary Mick Whelan said driver-only trains were ‘inherently unsafe’.
However, Transport Secretary Chris Grayling claimed the industrial action on Southern was politically motivated, saying Aslef had accepted driver-only operation (DOO) on the Brighton mainline.
The minister added in a letter to Brighton MP Simon Kirby that more than 60% of the trains on the Greater Thameslink Railway, which includes Southern, have DOO.
‘I recognise the very real concerns that you and your constitutents have about this, but we cannot allow the unions to dictate how or whether the railways should be modernised or not,’ Grayling wrote.