Part of plane's wing falls off during CityJet flight from London to Florence

Passengers looking out of the window of a Florence-bound flight were met with an unexpected view when part of the jet's wing fell off.

The 61 passengers on board the CityJet flight from London to Florence were terrified when they heard a loud bang shortly after take off, and a section of the left wing almost two metres long detached from the plane.

British journalist Cole Moreton was on board the flight, and described the confusion as passengers alerted cabin crew, who then appeared to inform the pilot.

"The bang made people jump and was alarming then we sat there thinking this isn't right, surely?" Moreton said to The Telegraph.

Despite the damaged state of the Avro Rj85, the pilot circled the Thames estuary and managed to land safely after discussions with maintenance experts on the ground.

A CityJet spokesman said the cover of the operating mechanism on the wing became partially detached just after the plane had taken off from London City Airport.

A replacement place was found, and the flight took off for Florence again about an hour later.

An internal investigation into what caused the problem is expected to take place.

Stuff.co.nz