A commuter claims to have captured footage of the drone over Heathrow Airport which caused flight chaos last night.
Around 40 flights were grounded for an hour shortly after 5pm after police received reports of a drone.
Matt Charter, who was travelling back from work in Southall on the A30 in Stanwell, spotted what he thought was a drone above near the Southern boundary at 5.54pm.
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Mr Charter, 24, of Wraysbury, Berkshire, said: "I was travelling home from work when I noticed the news about the disruption caused by the drone at Heathrow pop up on my phone.
"Me and my colleague who I was traveling home with then saw what I thought was a drone hovering in the sky.
"We friend started filming it and we pulled over before we filming it again closely at the A30 at Stanwell.
"It certainly was a drone as it was hovering stationary at about 300ft in the air and was flashing distinct red, green and white LED lights.
"It was quite a surprising five minutes."
A Heathrow Airport spokesman said that they were working with Air Traffic Control and the Metropolitan Police who are investigating the incident.
Metropolitan Police Commander Stuart Cundy, said: "Shortly after 5pm we received reports of a sighting of a drone at Heathrow airport.
"As part of our established response plans to such an incident, officers were swiftly deployed across the airport and we continue to work closely with colleagues from Heathrow Airport Limited.
“As a precaution, departures were stopped at the airport whilst initial enquiries were made.
"Once it was established it was safe to do so, departures were resumed just after 6pm and the airport is now fully operational."
He continued: “Our priority is to ensure that there is no ongoing threat to the safety of those at the airport and identify those responsible for this dangerous act.
“Police officers were amongst those who saw the drone and a full criminal investigation has been launched.
"We are carrying out extensive searches around the Heathrow area to identify any people who may be responsible for the operation of the drone.
“I want to be clear that the illegal operation of drones at an airfield is extremely dangerous.
"Under the Aviation Security Act it is an offence to endanger the safety of an aircraft, anyone found guilty of this offence could face a life sentence."
The incident came three weeks after major pre-Christmas disruption at Gatwick Airport which saw thousands of people stranded when drones were apparently sighted.