Southern Railway’s owners have lodged an appeal against a High Court decision to refuse an injunction to prevent industrial action by drivers.

A judge yesterday ruled that the industrial action, though disruptive, is legal because it was sanctioned through a lawful ballot.

But Govia Thameslink Railway (GTR) announced it has lodged an urgent application at the Court of Appeal against the decision not to allow ASLEF union’s strike action to be blocked.

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GTR is asking to stop a series of nine strike days by drivers which begin on Tuesday, December 13, and an overtime ban which took effect last week.

Members of Aslef, the train drivers’ union, are due to walk out for three days next week and for six days in January in a dispute over driver-only trains.

The action will bring all Southern services to a halt and affect hundreds of thousands of people.

Charles Horton, chief executive of GTR, said: “This industrial action is having a severe and significant impact on our ability to run our train services and causing massive disruption to the 500,000 passengers who travel with us every day.

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“We were granted permission yesterday by the Judge to make an urgent appeal and we have a duty to our passengers to do all we can to prevent the wholly unjustified industrial action continuing.

“Our passengers have suffered months of travel misery and we call again on the unions to call off their action and work with us to find a resolution to their dispute.”

Drivers started a ban on overtime this week which coincided with a three-day walkout by members of the Rail, Maritime and Transport union, leading to half of Southern services being cancelled.

Services continued to be hit on Friday even though the RMT strike ended at midnight.

The RMT is embroiled in a bitter dispute over the role of conductors while Aslef is opposed to driver-only trains.

Drivers from both unions are due to strike on Tuesday, Wednesday and Friday of next week and for six days in January.

No date has yet been allocated for the Court of Appeal hearing.