Officers were called to a multi-storey car park at Terminal 3 shortly after 8.10am this morning (December 7) with reports of multiple people being assaulted.
Armed police were dispatched alongside paramedic and fire brigade colleagues.
At the scene, a number of people were located having been sprayed with a substance that police believe is a form of pepper spray.
They have been taken to hospital with non-life changing or threatening injuries.
A man was arrested by armed response officers on suspicion of assault.
He remains in custody and enquiries continue to locate further suspects.
Cmndr Peter Stevens said: “At this stage, we believe the incident involved a group of people known to each other, with an argument escalating and resulting in a number of people being injured.
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“Our officers responded quickly and there will be an increased police presence at Heathrow Airport throughout the morning, to continue enquiries and ensure the safety of those in the area.
“We are not treating this incident as terrorism. I understand the public’s concerns and would like to thank those in the area for their cooperation this morning.”
Anyone with information about the incident is asked to call 101, quoting CAD 1803 7 DEC.
