A man found a USB stick on the street in London which had confidential security information about Heathrow’s airports last weekend.

Classified information regarding security protocols at Heathrow airport was discovered on a USB stick discarded on a London street over the weekend.

The memory stick contained an unencrypted 2.5GB of data with 76 folders with maps, videos and documents, and didn’t require a password to access the information, according to The Mirror, which was given the USB stick.

There were at least 174 documents with some marked as “confidential” or “restricted” but which could still be read.

It even contained information about the route the Queen takes when using the airport and security measures used to protect her, files disclosing every type of ID needed to access restricted areas, and a timetable of patrols used to guard the site against terror attacks.

Furthermore, the stick, found on the pavement of Ilbert Street in Queen’s Park, contained maps showing the location of CCTV cameras, routes and safeguards for cabinet ministers and foreign dignitaries and details of the ultrasound radar system used to scan runways and the perimeter fence.

Airport insiders were trying to determine if there had been an “incompetent data breach” or if the files had been accessed intentionally, according to The  Mirror.

The information was passed onto Heathrow intelligence chiefs and the man who found it has been interviewed by airport security chiefs.

A Heathrow spokesperson said in a statement: “Heathrow’s top priority is the safety and security of our passengers and colleagues. The UK and Heathrow have some of the most robust aviation security measures in the world and we remain vigilant to evolving threats by updating our procedures on a daily basis.

“We have reviewed all of our security plans and are confident that Heathrow remains secure. We have also launched an internal investigation to understand how this happened and are taking steps to prevent a similar occurrence in future.”

Heathrow was affected by British Airways’ IT outage last summer, which affected around 75,000 passengers. BA was forced to cancel flights from Heathrow and Gatwick airports. It later emerged that the reason for the outage was because an engineer had mistakenly switched off the power supply to a data centre and then turned it back on in an “uncontrolled fashion”.