The body of an aircraft stowaway has fallen out of the sky near London's Heathrow airport, landing in a garden reportedly right next to a shocked sunbather.

Key points: The man likely fell from the landing gear of a Kenya Airways flight, police say

The man likely fell from the landing gear of a Kenya Airways flight, police say A neighbour recalls hearing a "whomp" as the man landed in the London garden

A neighbour recalls hearing a "whomp" as the man landed in the London garden Kenya Airways describes the incident as "unfortunate" and says it will work closely with the relevant authorities

The man, who has not been identified, likely fell from the landing gear of a Kenya Airways flight on its way into Heathrow Airport, according to the Metropolitan Police Service.

The service confirmed officers were called to a home in Clapham in south London on Sunday after the man's body was found.

"At this point, police believe the man was a stowaway and had fallen from the landing gear of an inbound Kenya Airways flight to Heathrow Airport," police said in a statement.

"A bag, water and some food were discovered in the landing gear compartment once it landed at the airport."

Speaking to the BBC, a neighbour, who asked not to be identified, said the man fell a metre away from another resident who had been sunbathing in the garden.

He recalled hearing a "whomp", before discovering "blood all over the walls of the garden".

"So I went outside, and it was just then the neighbour came out and he was very shaken," the man said.

In a statement, Kenya Airways described the incident as "unfortunate" and said it would work closely with authorities in Nairobi and London as they investigated the case.

Stowaways have slim chance of survival

It is not the first death of its kind on flights to Heathrow.

Bodies have previously been found on the streets in the Richmond and Kew areas of London, which lie below the point at which many jets open their landing gear doors to put the wheels down on the Heathrow approach.

Many planes open their landing gear doors over the Richmond and Kew areas of London. ( Reuters: Eddie Keogh )

In 2015, the body of a man was discovered on the roof of a building in south-west London after falling from the undercarriage of a plane as it came to land from South Africa.

Three years earlier, a man from Mozambique fell from the undercarriage of a Heathrow-bound flight from Angola onto a street under the flight path near Richmond.

An inquest found that he may have survived freezing temperatures for most of the flight but was "dead or nearly dead" by the time he hit the ground.

Experts said the chance of a stowaway managing to avoid either being crushed by the wheels as they retracted after take-off or being frozen to death during the flight was very small.

Reuters/ABC