'OR Tambo Airport hasn't had stowaways in 10 years'

Acsa says it hasn’t had reports of stowaways departing from OR Tambo International Airport in a decade.

A British Airways’ A380 airbus flying over Cape Town. Picture: Supplied.

JOHANNESBURG - The Airports Company of South Africa (Acsa) says it has not had reports of stowaways departing from OR Tambo International Airport in a decade.

Acsa has boosted security at the airport after two men allegedly gained unauthorised access on a British Airways plane.

On Wednesday two stowaways managed to fly to London from Johannesburg by sneaking onto the undercarriage of a British Airways flight.

One man is said to have plunged to his death while another is being treated in a London hospital under police guard.

WATCH: Stowaway found on London rooftop.

They apparently had to withstand temperatures as low as 50 degrees below freezing point for 11 hours while clinging to the Boeing 747.

Aviation experts have described it as astonishing that the second man survived freezing conditions throughout the flight.

Acsa spokesperson Colin Naidoo said, "This is the first occurrence of an incident of this nature at the airport in 10 years. We are working with local and British authorities to establish the facts around the incident."

MYSTERY LOOMS OVER IDENTITIES OF SUSPECTED STOWAWAYS

Acsa says it's difficult to establish whether the two suspected stowaways were in fact South Africans.

The airports company says because the pair were found in London - it's up to British authorities to confirm their nationalities.

Naidoo said, "We are waiting for information from the British authorities. We don't know the identities of the stowaways yet."

Acsa says the claims are severe and that it's reviewing security at South African airports to identify any weaknesses.

Police also confirmed that they have been roped in to probe the allegations.