A memory stick containing confidential files dumped in the street has no cause for security concerns at Heathrow, the airport's boss has said.
An internal investigation has been opened into the incident after reports of a security breach came to light over the weekend.
However Heathrow chief executive John Holland-Kaye said the information has not compromised security and the airport remains "completely secure."
He spoke about the "disappointing" incident during the Commons Transport Committee meeting on Monday (October 30).
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"From the information that I have seen... that was on the USB stick that was reported in the papers, there was nothing there that causes us any security concerns," he said.
"So, from what I have seen, Heathrow is completely secure.
"We take safety and security very seriously and are very disappointed that this incident happened.
"We immediately set up an internal investigation to find out what happened, and that is ongoing.
"We have involved the Metropolitan Police in that investigation."
The device was spotted in Ilbert Street, Queen's Park , and handed into the Sunday Mirror.
Among the unencrypted files found on the 2.5GB memory stick included the Queen's route when using the airport, types of ID needed to access restricted areas and the location of CCTV cameras, tunnels and escape shafts linked to the Heathrow Express.
Fears were raised over terror threats after the sensitive information was found.
A security source told The Mirror : “In the wrong hands this would represent a profound threat in terms of terrorism or espionage."
In addition, an expert told the paper: "In the wrong hands it could potentially be very helpful and would save them a lot of time in planning an attack.”
A former counter-terrorism chief who specialises in airport security said this was a "huge security breach" and said "there are serious questions to be answered" as to why the unencrypted memory stick was taken off site.
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