A man has fallen to his death after clinging to the undercarriage of a passenger jet as it made the 8,000-mile, 11-hour trip from South Africa to London on Thursday, according to reports.
Police confirmed that the man fell into the roof of the offices of internet retailer Not on the High Street (above) in Richmond, west London.
The man was found lying on an electrical box on the building's roof. The plane was reportedly a British Airways 747 from South Africa.
Scotland Yard said in a statement: "We were called at 9.35am on Thursday 18 June to Kew Road, Richmond, to reports of a body discovered. Officers and the London Ambulance Service attended and found the body of a dead man on the roof of a business premises. The death is currently being treated as unexplained.
"A postmortem examination will be held in due course and inquiries are ongoing to establish the male's identity. No arrests have been made."
Police confirmed that a second man was found in a plane's undercarriage, although it is unclear if he was on board the same plane: "In regards to the male who survived, police were alerted at 8.28am on 18 June to reports of a suspected stowaway on a flight from Johannesburg to Heathrow.
"The man, aged believed to be between 25 to 30, has been taken to a west London hospital and currently remains in a serious condition. Inquiries are ongoing to establish the man's identity."
British Airways told BuzzFeed News in a statement that it was working with police to establish the facts of "this very rare situation".
When asked what measures the airline takes to prevent such incidents, BA said: "Safety and security is always our top priority. We review the security measures at every airport we fly to on a regular basis and will be working with the authorities in Johannesburg to establish what happened in this very rare incident."
A spokesman for Not on the High Street told BuzzFeed News: "The death is currently being treated as unexplained but early indications are that the body may be that of an airline stowaway."
"Officers and the London Ambulance Service attended and found the body of male on the roof of the premises.
"Enquiries are ongoing to establish the male's identity. Notonthehighstreet.com can confirm that the incident is unrelated to the business or its team members and are cooperating with the ongoing police enquiry."
BuzzFeed News understand that staff were not aware of the incident at the time and were informed by management.
In 2012, a man fell from the undercarriage of a British Airways flight from Angola to London on to a residential street in East Sheen, west London, near Richmond.
He was found with a single pound coin in his pocket and was later named as 26-year-old José Matada. It was unclear whether he died from hypothermia and exposure or from the fall. It took more than six months for his identity and the details of his movements to be revealed.
The police said in a further statement on Friday morning that the surviving man is aged 24 and was found in the undercarriage of a plane at Heathrow airport. He is in a "critical" condition.
But police were keen to stress that the surviving man may not be linked to the man who fell from the plane and died on Thursday, saying:
"At this time there is no evidence to link the death to the discovery of a stowaway in the undercarriage of a plane at Heathrow Airport; however, this is one line of enquiry into identifying the deceased and the circumstances of his death."
Police believe they know the survivor's identity and nationality but are waiting for confirmation before releasing any details.