The Oxford University graduate was just centimetres from the falling body, which left a crater in the garden of the £2.3 million ($A4.5 million) home he rents in Clapham, South London.
Speaking to The Sun, a neighbour said: “I was in the kitchen and there was a huge noise. It shook the kitchen.
“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.”
John, 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.
The corpse fell from the passenger plane at around 3.30pm on Sunday as it came in to land at Heathrow following a nine-hour flight from Nairobi.
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.
The body only narrowly missed a packed Clapham Common and High Street where families were out in their droves in the 30C heatwave.
John, who rents a room in the four-storey house from pal Bob Renwick, 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.
‘THE IMPACT WAS HORRIFIC’
“There were a few of us in the house at the time, and it was lucky only one of us was in the garden.
“Nobody would have survived being hit. The impact was horrific.”
John had been living in the property for around six months, moving in while working for Bob’s firm Plexi, based in Bermondsey, London, and Birmingham.
Another neighbour added: “I heard a whomp so I went to look out the window. At first I thought it was a tramp asleep. He had all his clothes on and everything.
“I had a closer look. I saw there was blood all over the walls of the garden and his head was not in a good way.”
The Clapham resident said a plane spotter, who had been following flight KQ100 on an app from Clapham Common, had seen the body fall and arrived almost at the same time as the police.
He added: “I spoke to Heathrow and they said this happens once every five years. There was a previous man who was frozen and this one, he was like an ice block.”
The Kenya Airways flight passed over the house just after 3.30pm on Sunday — descending to around 3500 feet (1066 metres) and flying at 321km/h as it prepared to land.
‘THE MAN WHO FELL FROM THE SKY’
Bob’s brother said John was “very badly shaken”.
He added: “It was a narrow miss. The garden isn’t very big.
“There was more than a lot of blood. It wasn’t pretty and caused a significant amount of damage.”
The force of the impact was so severe police were initially unable to tell whether the body was male or female.
It is now understood the man was wearing a blue T-shirt and jeans. Forensics examined the scene for five hours before removing evidence.
One female resident said: “There was an almighty bang. My husband went out into the street where my neighbour was standing on the phone to the police.
“He was really shaken up. He’d been in the garden when it happened, and the body must have landed so close to where he was.
“My husband came back in, and I asked him what was going on, and he said, ‘Haven’t you seen the man? The man who fell from the sky?’
“I wondered what he was talking about and went up to see for myself, and there in the middle of the lawn was a body of a man.”
The stowaway, who has not been identified, is believed to have been working at Jomo Kenyatta International Airport in Nairobi. Investigators are understood to have found CCTV footage of him.
A source told The Sun: “It looks highly likely he was an employee, as security has been beefed up and no one without a pass could get near a plane. He could have been a baggage handler or one of a number of staff given airside clearance.
“It’s possible that he could have bribed someone to get inside the perimeter, but this seems unlikely and the CCTV will hold the key.”
He is likely to have blacked out just 20 minutes after takeoff as oxygen levels fell and would have been frozen to death by temperatures of around -56.5C.
A source said: “There have been rare cases where stowaways have survived, but in the main they lose consciousness because of a lack of oxygen and hypothermia and then they fall when the wheels go down.”
A Department for Transport spokesperson said: “This is a shocking incident, and our thoughts are with those involved.
“While we do not comment on operational matters, we are liaising with the Kenyan authorities and the air carrier as they carry out their investigation into this incident.”
This article originally appeared on The Sun and was reproduced with permission