Urgent safety warnings have been issued after a number of cases of aircraft nearly hitting unmanned drones in Heathrow.

One such case in 2014 was classed as the most serious category, where a risk of collision was high.

On July 22, 2014 a plane making its way in to land at Heathrow Airport had a near-miss when it almost collided with a controllable drone.

The Airbus A320 was on its final approach to Heathrow when the pilot spotted a small black object fly over the aircraft’s wing, around 20ft away.

Thankfully, the plane landed safely and air traffic control was informed.

The incident happened at 700ft above ground level and efforts to trace the drone operator were not successful.

The near-miss was classed as category A - the most serious classification where a risk of collision was high.

A Heathrow spokesman told getwestlondon: “The unauthorised use of unmanned aerial vehicles (UAV) in proximity to an airfield is both irresponsible and illegal.

“Heathrow's top priority is the safety of our passengers and staff.

"The CAA (Civil Aviation Authority) recently published revised guidelines on the use of UAVs and we will continue to work with them and other partners to ensure that any violation of airspace rules is fully prosecuted.”

There have been many incidents involving aircraft and UAVs in recent years. On March 15 this year, at Heathrow, an Airbus A320 pilot spotted a black object in the sky while at 1,800ft. The drone passed over the passenger plane by around 50ft.

The CAA has launched a new drone awareness initiative in order to target the increasing number of recreational drone users in the UK.

Director of policy Tim Johnson said: “We want to embrace and enable the innovation that arises from the development of drone technology, but we must ensure that this is done safely, with all airspace users in mind.

"It is imperative that people observe the rules when operating a drone.

"Drone users must understand that when taking to the skies they are entering one of the busiest areas of airspace in the world - a complex system that brings together all manner of aircraft including passenger aeroplanes, military jets, helicopters, gliders, light aircraft and now drones.

"When doing so, they must be aware of the rules and regulations for flying drones that are designed to keep all air users safe."