Strikes by Southern train drivers will go ahead next week after the operator failed in its High Court bid to stop industrial action.
Southern's parent company, Govia Thameslink, had argued the Aslef-backed walkouts would breach customer rights.
The three days of strikes will be held from 0.01am on Tuesday, December 13 to 11.59pm on Wednesday, and all day Friday.
Aslef general secretary Mick Whelan said the decision meant it was time Southern came to the negotiating table.
He said: “Now the company should do the right thing and sit down with us and negotiate - properly, sensibly and in good faith - to do a deal for the benefit of passengers, staff and, yes, the company, just like ScotRail did with us earlier this year.”
Nick Brown, chief operating officer of Govia Thameslink Railway, said: "Naturally we are disappointed. The judge said that such unprecedented strike action by Aslef would cause massive disruption to the public.
"The judge also said the widespread use of trains using driver operation is perfectly safe both in Southern and elsewhere in the UK.
"We brought this action for the benefit of our passengers. The judge has given us permission to go to the Court of Appeal which we will now consider with our legal team."
Southern warned passengers they would face "increased disruption over the Christmas and New Year period".
