“T-Mobile had a national network failure,” said spokesman Dirk Wende.

In the Bonn headquarters all hell broke lose. Technicians frantically searched for the cause of the crash.

At 5.55 pm, two hours after the start of the network collapse, the first signs of an explanation appeared. Spokeswoman Marion Kessing told BILD: “The calls and texts service has been affected, but not land lines. The internet is still working. We can exclude sabotage, a hacker attack or computer virus.”

Customer help lines were jammed as millions tried to call in to complain about the crash, and T-Mobile’s website was overloaded.