The owners of Southern Railway have launched a High Court bid to block "unprecedented" strike action by drivers.

Members of Aslef are due to walk out for three days next week and six days in January in a dispute over driver-only trains, which will halt all Southern services.

Drivers have already started an indefinite ban on overtime which, coupled with a strike by the Rail, Maritime and Transport (RMT) union in a separate row over changes to the role of conductors, has 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 strikes go ahead.

In London on Wednesday, Govia Thameslink Railway (GTR) argued that the Aslef strikes unlawfully restricted EU law freedoms.

If GTR succeeds, it is understood it will be the first time that an injunction to prevent industrial action would be obtained in this country on that basis.

Hugh Mercer QC told the judge, Sir Michael Burton: "We do say that this is unprecedented strike action - three days this month and six consecutive days next month - after just returning to work."

The driver-only operation technology is widely used by other companies around the world and the rollout in this country is very far advanced, having started in August and due to end in three weeks.

No jobs or pay are at stake and the attempt to stop and reverse the rollout would adversely affect hundreds of regular passengers daily, the Gatwick Express and EU travellers, he said.

The judge said it was a "given" that the strikes would cause enormous disruption and loss, but if it was a lawful strike that was the effect.

Asked if there was any prospect of resolving the dispute out of court, Mr Mercer said: "There are things going on in the background and we simply don't know whether they are going to bear any fruit."

The judge replied: "Let's hope they do."

The hearing is due to last all day.

In papers seen by the Press Association, GTR cites Articles 49 and 56 to the Treaty on the Functioning of the European Union.

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.

Paul Plummer, chief executive of the Rail Delivery Group, which represents train operators, has 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."

The judge said he hoped to give his decision at 2pm on Thursday at the conclusion of argument.