A passenger plane has crash-landed short of a runway at Heathrow Airport, ripping off part of its undercarriage.
All 136 passengers and 16 crew escaped from the British Airways flight BA038 from Beijing. Eighteen people have been taken to hospital with minor injuries.
An airport worker told the BBC the Boeing 777 pilot, named later as Peter Burkill, 43, said he had lost all power and had to glide the plane in to land.
All BA short-haul flights from Heathrow have been cancelled and others delayed.
BAA, the Heathrow operator, said it hoped to return to "near normal operations" on Friday, but advised all passengers to contact their airlines for up-to-the-minute information.
The worker also said the pilot had told him all the electronics had also failed.
"He said he had no warning - it just went," the worker added.
"It's a miracle. The man deserves a medal as big as a frying pan."
BA refused to comment on the report and said it would not speculate on the cause of the crash.
Police say the incident was not terror-related.
Nearby Hillingdon Hospital said it had received 18 casualties, 12 women and six men. Some of them had been suffering from whiplash.
Four of those admitted were BA crew members, but the pilot was not thought to be among them.
By Thursday evening, 17 had been discharged, but one woman with suspected concussion was admitted overnight.
HEATHROW TRAVEL DISRUPTION
221 flights cancelled, including scheduled British Airways flights from Manchester Airport to Heathrow at 1540, 1705, 1850 and 1940
Many other long-haul flights departing and arriving late
24 incoming flights diverted to Gatwick, Luton and Stansted
For up-to-date information on later flights, contact your airline
Seven of those treated in hospital were British and three were Chinese. The nationalities of the others are not yet known.
The incident happened on the south runway at 1242 GMT, as Prime Minister Gordon Brown was due to leave Heathrow for China and India. His flight was delayed because of the incident.
Witnesses described the plane coming in very low and landing short of the runway, before skidding across grass and tarmac.
Part of the undercarriage, including two wheels were torn off, and there was some damage to the wings.
The runway was initially closed, but reopened later to take-offs only. The north runway remained open throughout the incident.
A telephone helpline has been set up for anyone concerned about friends or relatives on 0800 3894193.
The Department for Transport's Air Accidents Investigation Branch has launched an investigation.
In a statement, it said initial findings would be released within 48 hours, followed by a more detailed, but still preliminary, report within 30 days.
Paul Venter, who was on board the plane, said he had been aware of a problem just as the plane was about to land.
"I could hear the undercarriage come out, and the next moment the plane just dropped," Mr Venter said.
"When everything came to a standstill, I looked out of the window and the undercarriage was gone and the plane was on its belly."
Eyewitness John Rowland said: "The plane's wheels collapsed, doors were flown open.
"On its approach it took the runway too low, just missing the roof of my cab.
"It crashed into the runway, debris was flying everywhere, there was an enormous bang and it skidded sideways."
Another eyewitness, also a taxi driver, said the plane flew over "so low you would think you could lean out the window and touch it".
"It passed over my vehicle at something like 20ft and over the perimeter [fence] at 15ft before it plunged into the runway," he told the BBC.
Fire crews doused the plane in foam to prevent its fuel tanks catching fire.
And BA said the cabin crew had done an "excellent job" evacuating passengers via the emergency chutes.
BA helpline ONLY for anyone concerned about friends or relatives: 0800 389 4193 or 44 191 211 3690 from overseas
BA general enquiries: 0870 850 9850
Chief executive of BA Willie Walsh said he was "very proud" of the crew and the Boeing 777 was an "excellent aircraft".
"We train hard for incidents such as this, and all that training has paid off today," Mr Walsh said.
BAA said it was doing everything possible to avoid further delays and cancellations on Friday.
It said in a statement: "Heathrow has received special dispensation from the Department for Transport to make some night flights and have notified local residents who may possibly be inconvenienced by this exceptional circumstance."
Flights are expected to continue until about 0130 GMT on Friday.
Transport Secretary Ruth Kelly paid tribute to those involved in the incident and said she was "relieved" there had been no serious injuries.
"British Airways have assured me that they are doing everything possible for the passengers and crew involved," Ms Kelly said.
"The next step is to find out what happened and why."
Terminals: 4 (5 by Mar 2008)
Land area: 1214ha
Movements per year: 469,560
Passengers per year: 67.7m
World rank (by passengers): 3
Aviation expert Kieran Daly, from Flight International magazine, said not a single Boeing 777 had been lost in a crash since the aircraft was launched in 1995.
A total of 221 flights out of a normal 1,300 were cancelled on Thursday, Heathrow's operator BAA said. Most of those were to short haul destinations - just eight were long haul.
A further 24 flights bound for Heathrow were diverted to Stansted, Gatwick and Luton Airports.
John McDonnell MP, whose Hayes and Harlington constituency includes Heathrow, said the incident underlined concerns about extending the airport.
"This is a near miracle that neither passengers or anyone on the ground has been seriously injured," Mr McDonnell said.
The plane involved is one of 43 Boeing 777s in BA's fleet. It is believed to be about six years old.