The pre-Christmas drone attack that brought chaos to Gatwick is thought to have been an “inside job”.

Police reportedly believe a current or former airport employee was behind the incident on December 19 that grounded aircraft over three days, with 1,000 flights cancelled and 140,000 passengers affected.

Analysis of police witness reports, including from the most senior members of staff at the airport, have led officers to believe that the drone was probably operated by someone who knew the layout of the site, according to The Times, quoting Whitehall sources.

The drone was seen swooping past the air traffic control tower, where controllers could not photograph or film it due to a ban on mobile phones. Gatwick staff on the ground also claimed that it appeared to be taunting them by flying low overhead and flashing its light in their direction.

It is now thought that the drone also “hid” behind buildings and structures where it could not be reached by the military-grade anti-drone equipment brought in to defeat it, according to a Whitehall insider.

“[The drone pilot] knew the blind spots for it, where it could not be ‘hit’. It was clearly someone with really good knowledge of Gatwick, someone who had worked there. Hypothetically it could have been a disgruntled employee,” the source said.

A second Whitehall source reportedly said: “The thinking is that it is someone who had good knowledge of the airport layout. The ‘disgruntled employee’ theory is running high.”

One theory is that the operator of the hostile drone, which has never been recovered, may have been flying it from within the airport boundary, the insider added.

The drone repeatedly appeared and disappeared from December 19 to 21, raising the suspicion that when it vanished the perpetrator was grounding it to change batteries or put it on charge while deploying a second model.

The idea that there may have been two drones is supported by witness testimonies reporting that at one point different coloured lights could be seen from what appeared to be two devices over the airfield.

It is thought that the drone – or drones – used in the Gatwick disruption was either a self-built or a modified commercial version.

A College of Policing review into Sussex police’s handling of events has been promised by the end of this month.

A Sussex police spokeswoman told the newspaper: “We are keeping an open mind about who is responsible and their motives.”

The government yesterday announced an extension of drone no-fly zones around airports from March 13 together with new powers to stop and search suspected rogue drone operators.

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