An investigation has revealed the engine coverings on the British Airways plane which was forced to make an emergency landed had been left unlatched during maintenance.

The Air Accident Investigation Branch today said the error had not been identified prior to the departure of the Heathrow to Oslo plane last Friday.

The initial report into the incident, which resulted in one engine being engulfed by flames and passengers being evacuated via emergency slides, said the cowls (engine covering) had detached.

This punctured the fuel pipe on the right engine and damaged the airframe and some of the aircraft systems.

The report said: “The flight crew elected to return to Heathrow. On approach to land an external fire developed on the right engine.

“The left engine continued to perform normally throughout the flight.

“The right engine was shut down and the aircraft landed safety and was brought to a stop on runway 27R. The emergency services quickly attended and extinguished the fire in the right engine.

“Subsequent investigation revealed that the fan cowl doors on both engines were left unlatched during maintenance and this was not identified prior to aircraft departure.”