A signal controller at the centre of a probe into a fatal German train crash has admitted playing a game on his mobile phone just before the head-on collision, it has emerged.

The man was detained on Tuesday after developments in the investigation into Germany’s biggest train crash since 1998.

He faces possible charges of causing death through negligence.

The collision in Bavaria in February left 11 dead and many injured.

Investigators said the man “turned on his mobile phone during his shift on the morning of the accident”.

Members of emergency services work at the site of the two crashed trains near Bad Aibling

Rescue workers at the scene

The controller “started an online computer game and played actively … until just before the collision of the trains”, the investigators added.

The man admitted to playing the game but denied being distracted by it, said the statement.

But the prosecutor’s office said it could be expected that he was not paying attention to a critical traffic intersection.

The controller gave the trains an incorrect signal and then hit the wrong buttons when issuing a distress signal, it is alleged.

It meant the distress signal was not heard by the train conductors, the prosecutor’s office said.

The trains, carrying about 150 people, crashed at high speed between the spa town of Bad Aibling and Kolbermoor, near the Austrian border.

The investigation is continuing. No evidence of technical problems has been found to date.