The owners of Southern Railway will launch legal action today in a bid to halt a series of crippling strikes by train drivers, using a nine-year-old European case as part of its argument.
Members of Aslef are due to walk out for three days next week in a dispute over driver-only trains, which will halt all Southern services.
Drivers yesterday started an indefinite ban on overtime, which, coupled with a strike by the Rail, Maritime and Transport union in a separate row over changes to the role of conductors, led to around half of Southern's services being cancelled.
The disruption is set to continue for the rest of the week, and hundreds of thousands of rail passengers will face the biggest delays for years if next week's drivers' strikes go ahead.
Govia Thameslink Railway (GTR) will argue in the High Court that the Aslef strikes unlawfully restricts EU law freedoms.
In papers seen by the Press Association, the company cites Articles 49 and 56 to the Treaty on the Functioning of the European Union.
The company says no passengers will be able to travel on Southern services on at least the days affected by the strikes, affecting around 30,000 people travelling to and from Gatwick Airport every day.
It is understood the company will use the precedent of a 2007 European case about Baltic ferry workers to argue that the strikes will breach passengers' rights to travel around the EU.
Viking, a Finnish ferry operator, brought the case against the International Transport Workers' Federation, which was trying to prevent the company from reflagging a vessel in Estonia to take advantage of lower wages there.
The case upheld the right to strike but ruled that the right was restricted if a strike unjustifiably infringed on the fundamental right to move freely around the EU.
Members of the RMT confronted Transport Secretary Chris Grayling when he gave a speech on Tuesday on the Government's plans to give train operators control of track maintenance.
The RMT criticised Mr Grayling for refusing to meet unions unless they called off the strike.
General secretary Mick Cash said: "Our guards' members on Southern Rail remain rock-solid and absolutely determined in their action in defence of rail safety.
"The union repeats its demand for Chris Grayling and his rail minister to get out of their bunker, stop the mud-slinging and take up the offer from RMT for direct talks to sort out the worsening crisis on Britain's biggest rail franchise."
Paul Plummer, chief executive of the Rail Delivery Group, which represents train operators, said: "Thousands of passengers are suffering more delays and disruptions thanks to more needless strikes by the unions.
"The truth is that these strikes hitting Southern customers are not about safety, not about jobs, and not about customer service.
"Trains where drivers close the doors are safe. All the independent safety experts say so. A third of trains across Britain operate this way and have done so safely for 30 years, and run in other countries around the world."