A British Airways plane crash at London's Heathrow airport in January was likely caused by ice in the plane's fuel system, a report into the incident said.

The accident, which seriously injured one passenger when the plane landed 1,000 feet short of its intended runway, was not the fault of the flight crew, the Air Accidents Investigation Branch (AAIB) said in an interim report into the incident.

It also ruled out problems with the amount or quality of the fuel, focusing instead on the build up of ice in the system. The Boeing 777 aircraft, which used engines from Rolls Royce, had flown into London's Heathrow from Beijing.

"There are no safety recommendations specific to British Airways. We will work closely with the relevant regulatory authorities and comply with any requirements issued to all operators (of the aircraft)," the British carrier said in a statement.

Its shares were down 4 percent at 251 pence by 1504 GMT, hit by the weak pound and the rising price of oil.

The AAIB report said the incident was unique and the investigation would continue.

"Extensive data analysis has revealed that not only has there never been a previous occurrence of this type on the Boeing 777, but also that this is the first known occurrence of this nature in any large modern transport aircraft," it said.