The navy helps police after sightings of a drone quickly halted flights at Heathrow airport on Tuesday.
Scotland Yard stated a “full felony investigation” had been launched into the incident – and that officers had been amongst these to see the drone.
Departures from the west London airport had been suspended for about an hour.
It comes after hundreds of passengers had been caught up in disruption at Gatwick Airport final month following stories of drone sightings.
Heathrow airport, which can also be working with the Met Police, stated it was monitoring the scenario and apologised to passengers affected by the disruption.
Talking on Wednesday morning, the airport stated “enterprise was again to regular”.
The Met’s Commander Stuart Cundy confirmed navy help had been introduced in however wouldn’t talk about techniques intimately.
He stated the drone sighting was reported simply after 17:00 GMT, with departing flights stopped as a precaution whereas preliminary inquiries had been made.
“We’re finishing up intensive searches across the Heathrow space to determine any individuals who could also be liable for the operation of the drone,” he stated.
“The unlawful operation of drones at an airfield is extraordinarily harmful.”
Transport Secretary Chris Grayling said in the course of the incident that he was in touch with the airport in regards to the drone sighting, and had spoken to the house secretary and defence secretary.
BBC cameraman Martin Roberts, who works with drones, stated he was driving on the M25 previous Heathrow airport at about 17:45 GMT when he noticed what he believes was a drone.
“I may see, I might say round 300 toes up, very vibrant, stationary flashing crimson and inexperienced lights, over the Harmondsworth space,” he stated.
“I may inform it was a drone – these items have gotten fairly distinctive lights – not a helicopter.”
Gatwick said last week that it had spent £5m to stop future assaults. Heathrow additionally confirmed it might be shopping for programs to protect in opposition to drones.
And it was announced this week that police could be given new powers to deal with the unlawful use of drones.
In gentle of the Heathrow incident, British Airline Pilots’ Affiliation common secretary Brian Strutton known as on ministers to additional strengthen drone laws and to make sure airports invested in safety expertise.
“It is time to act swiftly and decisively,” he added.
Talking to ITV, Cupboard Workplace minister David Lidington stated: “Clearly, the federal government is wanting on the legislation to see whether or not there are methods during which it could possibly be strengthened.”
He added that airports additionally wanted to “step up” funding in expertise to detect and cease drones from flying.
BBC transport correspondent Tom Burridge stated whereas the “important” incident didn’t trigger the identical disruption as at Gatwick, it raised the query of how UK airports can cope with drones.
Whereas they’re wanting on the newest expertise, it’s clear they’re “enjoying catch-up” he stated – including that the aviation business had been calling for “drastic motion on this for months”.
Alice Evans, BBC London, at Heathrow
A few hours after the primary stories of a drone within the skies above Heathrow, it was enterprise as standard within the Terminal 5 departure lounge – in a low blow to Gatwick, one member of workers informed me it is as a result of “we’re an excellent airport”.
Though flights had been up and operating once more fairly rapidly, there are nonetheless loads of passengers who’ve confronted disruption.
A kind of is Catriona Walsh, who was on a flight from Basel.
Ms Walsh, who was doing a few days of labor regardless of being on maternity depart, stated her flight was held on the runway for about 50 minutes as workers informed passengers in regards to the drone.
“It was all calm – irritating moderately than worrying,” she stated.
Michael, a fellow passenger on the flight who didn’t wish to present his surname, was much less optimistic.
“I used to be nervous I might need to camp right here,” he stated.
He stated the issues right here and at Gatwick have proven “precisely the best way to shut a rustic – this nation – down”, including that police have to “simply shoot drones down” as quickly as they’re sighted.
Greater than 140,000 passengers at Gatwick had been affected throughout 36 hours of chaos between 19 and 21 December.
About 1,000 flights had been cancelled there over three days because of the drone sightings.