A passenger's hand luggage, which had been left unattended, was the cause of the major security alert which closed Luton airport for several hours.

A suspicious object was found during a routine x-ray security search. The passenger was questioned by the police but was unable to account for the item and confirmed the bag had previously been left unattended.

The item, which was rectangular in shape, displayed a large amount of organic mass, power sources and several electronic cables.

It sparked a full-scale emergency evacuation of the airport terminal and flights were diverted to Stansted in Essex and Birmingham.

The airport was closed for more than four hours as passengers were forced to wait outside as a specialist military Explosive Ordnance Detection unit was called in.

A controlled explosion was carried out.

Bomb squad vehicles parked outside Luton airport. Credit: Gavin Harper

"The situation came about because of the combination of suspicious items in the hand luggage, an inadequate explanation and the fact that the passenger who owned the bag also told officers he had left it unattended while he went elsewhere in the terminal."

Insp Dave Ford, Airport Policing Unit
Passengers waiting outside Luton airport. Credit: James Blake

Luton airport said the terminal was now operating normally with flights in and out.

"London Luton Airport would like to thank passengers for their patience and cooperation and remind the travelling public to remain vigilant and aware in this time of heightened security."