The stowaway who fell from a Kenya Airways plane in London is likely to have been an employee at Nairobi's main airport, a Kenyan official has said.

On Sunday, a plane was flying from Kenya's capital to Heathrow Airport when a body fell into a garden.

The impact zone in Clapham, South London, was just one metre from where a man was sunbathing in his backyard.

According to The Sun, John Baldock was in his garden when the frozen body fell from the landing gear of a Kenyan Airways jet coming to land.

The Oxford University graduate was little more than an arm's length away from the falling body, which left a crater in the garden of the £2.3 million ($A4.5 million) home he rents.

Timeline of stowaway's death in London. Picture: The Sun
Timeline of stowaway's death in London. Picture: The Sun

According to Kenya's Civil Aviation Authority chief, the deceased man who fell from the plane probably had legal access to the airport, with a post-mortem likely to be carried out in the next few days.

The director general of the Kenya Civil Aviation Authority, Gilbert Kibe, told BBC Africa there was tight security at Nairobi's Jomo Kenyatta International Airport, therefore it was unlikely an outsider would have crossed the runway and climbed into the plane without being noticed.

A sunbather was just one metre away from being crushed when a frozen aeroplane stowaway plunged 1000 metres into his garden.
A sunbather was just one metre away from being crushed when a frozen aeroplane stowaway plunged 1000 metres into his garden.

"They do check every part of the aeroplane, including the undercarriage, the wheels, the brakes, the tyre condition, the wheel well that is above there. They inspect everything. So when those checks were being done, it is not likely that person was there, otherwise he would have been seen.

"So at which point the person gained access, that is the mystery," Mr Kibe said.

Airline workers said a bag, water and stash of food were later found in the plane's landing gear - where the stowaway had been hiding.

A plane spotter, according to the BBC, had been following the Kenyan Airways flight on a tracking app and saw the body fall.

The spotter, who arrived to the scene at the same time as police to inspect the impact zone, said one of the reasons the body was so intact was "because his body was an ice block".

Speaking to The Sun, a neighbour said there was a huge noise when the body dropped that "shook" his kitchen.

John Baldock was in his back garden when the frozen body fell from the landing gear of a Kenyan Airways jet coming to land at Heathrow on Sunday.
John Baldock was in his back garden when the frozen body fell from the landing gear of a Kenyan Airways jet coming to land at Heathrow on Sunday.

"I thought my house was falling down. I went upstairs and looked out the window and saw the body.

"John had been out sunbathing. He is a lodger and is friends with Bob the owner.

"I saw John outside, he was shaking and trembling. He wasn't saying anything. He could hardly speak.

"My husband called the police. It was horrific."

Mr Baldock, a software engineer in his 20s who previously worked for Ticketmaster, has since fled back to his hometown of Exeter, Devon as he comes to terms with the near miss.

A significant dent in the ground remains from where the stowaway landed after falling from the Kenyan Airways jet.
A significant dent in the ground remains from where the stowaway landed after falling from the Kenyan Airways jet.

He is said to be struggling to come to terms with the ordeal and is being comforted by parents Michael and Phi.

John's friend said: "He was so lucky not to be hit and killed. The impact obliterated the body.

"He didn't even realise what it was to begin with. He was asleep and then there was a huge impact.

"The body literally landed one metre away from him and was obliterated. My friend was very shaken."