A body has been found inside a passenger jet which landed at Heathrow Airport after flying from South Africa.
British Airways said the body was discovered in the landing gear bay of the BA Boeing 747 at the end of a flight from Cape Town.
Metropolitan Police have confirmed that the man was not a member of the flight crew, or a passenger on the plane, but added that they are not treating the death as suspicious.
BA said it was working with South African authorities and Cape Town airport to investigate how the incident took place.
A spokesman for BA said: "This is a very rare and sad event and our thoughts are with the individual's family."
It is believed that the deceased could be a person who was spotted climbing over a fence at Cape Town International Airport, before heading towards a BA plane.
Airports Company South Africa (ACSA), which runs the airport, said it was carrying out an investigation.
An ACSA spokesman said: "The airport immediately responded and, as a security patrol officer attempted to apprehend the man, he ran in the direction of a British Airways aircraft already in its holding pattern ready for take-off.
"For safety reasons the security officer could not approach the aircraft. A search of the airfield was immediately conducted but the person was not found.
"British Airways, in addition to various other parties, were notified. Further sweeps were conducted of the runway and the broader airfield.
"This morning, reports from London's Heathrow Airport confirmed that a stowaway was found on board a British Airways aircraft. The person was found dead."