Investigators are trying to find the cause of the blaze, which took place months after the aircraft was grounded worldwide over a battery problem.

Heathrow’s runways were closed for 90 minutes on Friday, and some evening flights delayed by more than six hours.

Ethiopian Airlines took delivery of four Dreamliners in 2012.

The company said its plane had been parked at Heathrow for eight hours before smoke was spotted.

“We have not grounded any of our aircraft,” the carrier said in a statement.

“The incident at Heathrow happened while the plane was on the ground… and was not related to flight safety.”

The Dreamliner has been moved to a special hangar away from the terminals to allow the investigation to take place.

The UK’s Air Accidents Investigation Branch of the Department for Transport is expected to lead the inquiry, with Boeing, the American Federal Aviation Authority, the US-based National Transportation Safety Board and Ethiopian Airlines also taking part.

No time frame has been given for the probe.

Investigators will hope it is not a recurrence of the problems with its lithium-ion batteries that grounded the entire global fleet of 787s for three months earlier this year, said BBC News correspondent Richard Lister.

Several aviation experts have suggested that the fire appears to have broken out some distance from the two batteries.

Fire-retardant foam was sprayed at the airliner and an area on top of the fuselage in front of the tail appeared to be scorched.

‘Negligible delays’Passengers flying from Heathrow are being advised to call their airlines.

But most flights are expected to leave as planned, with airport operator BAA reporting “negligible” delays of around 10 minutes to some services.

Forty-two short-haul flights were cancelled, with most passengers put on alternative flights or carriers to their chosen destinations, a spokesman said.

Heathrow said no passengers had been on board the parked aircraft, named the Queen of Sheba, at the time of the fire.

Thomson Airways became the first British carrier to operate the aircraft earlier this week and is taking delivery of eight of the planes.

But Thomson said one of its Dreamliners travelling to Florida returned to Manchester Airport on Friday as a precautionary measure after the plane “experienced a technical issue”.

British Airways also recently took delivery of the first two of its 24 Dreamliners.

Virgin Atlantic said it “remains committed” to taking on the first of its 16 Dreamliners in September 2014.

Other Dreamliner operators include United Continental, Japan Airlines, All Nippon Airlines, Air India and Poland’s LOT.

Modifications madeThe Dreamliner was marketed as a quiet, fuel-efficient aircraft carrying between 201 and 290 passengers on medium-range routes.

It was due to enter passenger service in 2008 but it was not until October 2011 that the first commercial flight was operated by Japan’s All Nippon Airways.

All 50 Dreamliners in service worldwide were grounded at the start of the year following two separate incidents concerning its batteries.

On 7 January, a battery overheated and started a fire on a Japan Airlines 787 at Boston’s Logan International Airport. Nine days later, an All Nippon Airways 787 had to make an emergency landing in Japan after a battery started to give off smoke.

Boeing modified the jets with new batteries and flights resumed in April.

The batteries are not used when the 787 is in flight.

They are operational when the plane is on the ground and its engines are not turned on and are used to power the aircraft’s brakes and lights.

Boeing said in April it may not been able to identify the root cause of the battery issues but said its modifications would prevent the problems reoccurring.