Firefighters are in the final stages of putting out a major blaze at a hangar at Norwich International Airport.

The fire had broken out more than 12 hours earlier and threatened to ignite two aircraft filled with aviation fuel.

Crews spent much of Sunday taking apart the roof of the hangar and using jets and foam to douse the flames after the blaze spread to the building’s ceiling cavities.

By midday more than 70 firefighters were tackling the blaze, which was burning close to a Boeing 737 and an Airbus filled with more than 5,000 litres of aviation fuel.

Firefighters were alerted at 9.43am and said there were contingency plans to remove the planes if necessary, although they added that any attempt would be difficult because of scaffolding around the building.

Fire service incident commander Greg Preston confirmed that the hangar had split in two, but added that the roof remained intact, and no damage had been done to either aircraft.

“The incident has been scaled right down now, but two aerial platforms and water carriers remain in place, as firefighters have begun the process of dampening down.

“We successfully contained the fire and prevented it from spreading to the aircraft and the aviation fuel. One aircraft has been removed and placed elsewhere in the airport, but the other cannot be relocated due to the hangar splitting in two.

“The investigation into what caused the fire is ongoing and should be completed tomorrow. It was a slow-burning blaze, and is related to the fabric of the building.”

The hangar is used by KLM Engineering and Air Livery, and is on Liberator Road, with a number of shops and other airport hangars nearby.

Norwich police were notified of the incident but the fire is not being treated as suspicious.

A spokesman for Norwich International Airport said: “The fire is being controlled by the fire services, and is taking place in an Air Livery hangar. The airport and services are not affected.”