Hundreds of passengers suffered disrupted journeys after sightings of a suspected drone grounded flights for around an hour at Britain's busiest airport.
Airport chiefs apologised for the disruption to passengers.
A Heathrow spokesperson said: “We continue to work closely with the Met Police to respond to reports of drones at Heathrow.
"Based on standard operating procedures, working with Air Traffic Control and the Met Police, we have resumed departures out of Heathrow following a short suspension."
The sightings came four days after both Heathrow and Gatwick reported they were investing millions of pounds in equipment to prevent future flight disruption.
Just before Christmas, Gatwick was forced to close for three days because of drone sightings, grounding about 1,000 flights.
With planes normally taking off at frequent intervals, the disruption is likely to have knock-on effects for the rest of the evening.
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