BOTH runways at Heathrow airport were shut down this morning after a British Airways plane had to make an emergency landing.
One eyewitness described see one engine on fire and amateur footage shows smoke pouring out of the rear of the plane as it returned to land shortly after take-off.
Heathrow said that all passengers and crew had been safely evacuated from the plane following the incident at about 9am today.
There was speculation that the aircraft, which was flying from Heathrow to Oslo, had run into a flock of birds.
One runway has already reopened but one remains closed.
Emergency vehicles surrounded the plane and emergency chutes could be seen being deployed.
London Fire Brigade said a crew from Heathrow fire station had assisted Heathrow Airport's fire service with "an aircraft fire".
"We believe the fire is now out," it added.
The plane was on Heathrow's northern runway which remained shut. Later the southern runway reopened.
TV pictures showed smoke billowing from the stricken aircraft while it was airborne.
Passengers on resumed flights at Heathrow were being warned to expect delays of 30-60 minutes as well as 30 minutes of aircraft taxiing time.
Eyewitnesses described seeing smoke billowing from the plane, with the right engine on fire.
Clive Cook, who lives on the Heathrow flight path, told Sky News: "The actual engine itself was on fire.
"This plane was coming over and suddenly the tone of the engine changed dramatically, and I could almost say it sounded as if it was like a blowout, or an explosion.
"I'm absolutely certain that as it came through the clouds, and I looked up ... the right engine was on fire, it wasn't smoking, it was actually on fire."
Mr Cook said he saw the plane over the Thames at Battersea as he was taking his daughter to nursery.
Another eyewitness, named only as Jamie, was working in his garden near to Stamford Bridge, Chelsea, when he saw the plane.
He told Sky News: "All of a sudden we heard this almighty noise. It was like a fire jet going over. We could just see the right engine on fire - it was absolutely horrendous to see.
"You don't see things like that every day, it's incredible really.
"Your thoughts are with the people - if we could hear it that badly then what were the people going through on that plane?"
He said he thought the plane was just a few thousand feet above the ground and added: "It was below the clouds at this stage. To see an aircraft on fire - it wasn't good to watch."
BA said the Airbus A319 aircraft was carrying 75 customers and that it landed safely at Heathrow.
"The BA762, Heathrow to Oslo service, returned back to Heathrow shortly after take-off due to a technical fault," BA said in a statement.
"The aircraft landed safely and emergency slides were deployed ...we will be carrying out a full investigation into the incident."