Southern Rail workers have announced they will strike for three days in December, certain to cause Christmas chaos for travellers and commuters.
Strikers from the Rail, Maritime and Transport union (RMT) said they would stage industrial action for three days from 22 December, and three more days from New Year's Eve as part of the long-running feud over the role of conductors.
A 48-hour strike is due to start at midnight on Friday, with Southern due to run an extra 60 trains over the weekend in an attempt to cope with the disruption.
There is likely to be a restricted service, with many routes having fewer trains or none at all.
Southern says moving guards to a new role of on-board supervisor will improve services to passengers, with responsibility for closing train doors switching to drivers. But workers say safety will be compromised, and fear job losses.
In response to the latest announcement from the RMT Union a spokesman for Southern said:
“Not content with causing months of misery, the RMT has now hit a new low and is determined to cancel Christmas for the travelling public. These latest strikes will not just hit families wanting to get home for Christmas but also the shops and businesses for whom Christmas is their busiest time.
"These strikes are spiteful, vindictive and pointless given the majority of conductors have now signed up to the new on-board role. This has never been about safety; it’s purely about the RMT hanging on to outdated working practices and union power."
A national protest against Southern Rail's plans took place in London earlier this week.
Jeremy Corbyn turned up to the meeting of 200 strikers in parliament to show his support.The Labour leader has previously called for the railways to be brought back into public ownership.
Govia Thameslink Railways (GTR) and RMT said they were both ready to talk, but no meeting has been set. GTR said it would withdraw an offer it made if the strikes go ahead; it promised a £2,000 jobs bonus, above-inflation pay increases and made some guarantees on jobs.
But Mick Cash of the RMT rejected the offer, saying it is "completely meaningless" and the £2,000 payment was a bribe.