Details of 18 near misses between aircraft and drones have been revealed, as it emerged new  technology to combat the gadgets is in place at Heathrow.

Four of the incidents investigated by the UK Airprox Board (UKAB) involved airliners which were approaching the west London hub.

A pilot of an Airbus A380 spotted a large “commercial drone” pass along the right side of the aircraft within 20 metres at an altitude of 3,400 feet.

The UKAB assessed that the drone was being flown in a way which was “endangering other aircraft” and concluded that the incident on July 22 last year involved the highest risk of collision.

Drone stockThe exclusion zone for drones around airports will be extended to a 5km-radius (John Stillwell/PA)

Another category A near miss featured an Embraer 190 aircraft at an altitude of 800 feet as it was coming into land at Glasgow Airport on September 7.

A “shiny white drone” was flown immediately above the plane at just 15-30 metres away.

The UKAB concluded that a “definite risk of collision had existed”.

In a bid to stop a repeat of the problem, an anti-drone system placed on top of a commercial vehicle has been deployed at Heathrow.

The AUDS (Anti-UAV Defence System) is able to detect, track and ground drones and has been designed to stop them being used for terrorist, espionage or other malicious activities.

Similar equipment has been pictured on the roof of Gatwick’s South Terminal.

A Heathrow spokeswoman said: “Heathrow has always worked closely with the Government and Metropolitan Police to monitor and mitigate against threats to the airport, including the irresponsible use of drones.

“In the interests of safety, we do not comment on issues relating to security at the airport.”

Assessments of 18 near misses with drones between July and October were included in the UKAB’s  latest monthly report.

Aviation minister Baroness Sugg said: “The actions of these drone users were not only irresponsible, but illegal.

“The law could not be clearer that this is a criminal offence and anyone endangering others in this way faces imprisonment.”

There were 120 near misses between drones and aircraft reported in the year to December 4 2018, up 29% on the total of 93 in the whole of 2017.

Just six incidents were recorded in 2014.

There is growing concern about drones being flown near airports after recent disruption.

Multiple sightings of the gadgets caused flights to be grounded over 36 hours at Gatwick in the run-up to Christmas, while departures at Heathrow were suspended for an hour last week after a drone was spotted.

In a bid to stop a repeat of the problem, an anti-drone system placed on top of a commercial vehicle has been deployed at Heathrow.

Drones close Gatwick airportCounter drone equipment on a rooftop at Gatwick airport (John Stillwell/PA)

The AUDS (Anti-UAV Defence System) is able to detect, track and ground drones and has been designed to stop them being used for terrorist, espionage or other malicious activities.

Similar equipment has been pictured on the roof of Gatwick’s South Terminal.

A Heathrow spokeswoman said: “Heathrow has always worked closely with the Government and Metropolitan Police to monitor and mitigate against threats to the airport, including the irresponsible use of drones.

“In the interests of safety, we do not comment on issues relating to security at the airport.”

Existing rules for drone users include not flying near airports, staying below 400 feet and flying at least 50 metres away from buildings and people.

Last week, the Government announced a package of measures designed to give police extra powers to combat drones.

The exclusion zone around airports will be extended to approximately a 5km-radius (3.1 miles), with additional extensions from runway ends.

Ministers also announced that from November 30, operators of drones weighing between 250g and 20kg will be required to register and take an online drone pilot competency test.