A flight to London has been diverted after pilot overheard 'suspicious talk'.

Three men who were passengers have been detained in Germany after their EasyJet flight from Ljubljana, Slovenia to London was diverted to Cologne.

The plane landed on Saturday night after passengers reported that the men were talking about “terrorist matters”, according to a police the statement.

Police carried out security checks of the aircraft and questioned passengers after all 151 passengers were evacuated safely from the Airbus 319 aircraft using emergency slides, the airport said in a statement on its website.

Six aircraft were diverted to other airports as a result of the police investigation, the airport said. It said air traffic was affected for several hours as a result of the incident.

Federal police seized a backpack that belonged to one of the men, and exploded it outside of the aircraft, police said.

They gave no information on the contents of the backpack and said officials continued to investigate the backpack.

The men continued to be questioned late on Saturday evening. Other passengers were also being questioned, police said.

Bild newspaper quoted a spokesman for the German federal police as saying the pilot decided to land the aircraft in Cologne after passengers told airline personnel they had heard the men using words including “bomb” and “explosive”.