A three-year-old girl is among those who were treated by ambulance crews after a group of men used pepper spray on a woman they had robbed of her suitcase at Heathrow Airport.
Officers were called at 8.11am on Sunday to reports that multiple people had been assaulted by a group of men at the multi-storey car park at Terminal 3.
Armed officers called to the scene found several people who had been sprayed with what the Metropolitan Police said is believed to be a type of pepper spray.
One of the 21 patients the London Ambulance service treated was a three-year-old girl, police said, and five were taken to hospital.
Their injuries are not believed to be life-changing or life-threatening.
A 31-year-old man who was arrested on suspicion of assault remained in custody on Sunday afternoon, police said.
Officers said the man was arrested by 8.20am, within nine minutes of the report being received.
Witness Tom Bate told the BBC he had been waiting to be picked up from the car park when he saw “young men dressed in black darting through the crowd”.
He said he felt a burning at the back of his throat after they left, with other people nearby beginning to cough.
Officers continue to hunt for other suspects, but Scotland Yard confirmed the incident is not being treated as terrorism.
“I’m so glad to hear now that it’s not terrorism because it felt like I was in the middle of an attack – it was pretty intense,” Mr Bate told the BBC.
Footage on social media appeared to show a man being handcuffed by an armed officer while another searched him.
Commander Peter Stevens said: “Our team have been working at pace today to review CCTV from the area and speak with witnesses at the scene.
“At this stage, it’s understood that a woman was robbed of her suitcase by a group of four men, who sprayed a substance believed to be pepper spray in her direction.
“This occurred within a car park lift, with those in the lift and surrounding area affected by the spray.
“Our officers are working to determine the full circumstances around what happened but we do believe this to be an isolated incident with those directly involved known to each other.
“We appreciate that this has been a concerning incident and I commend the actions of the emergency services and members of staff at Heathrow Airport.”
By midday, dozens of passengers were waiting at the terminal’s bus stop for shuttles to the long-stay car park and elsewhere.
One family, who did not wish to be named, said they had waited for three hours at the bus stop after their flight landed at around 8am.
Heathrow staff handed out bottled water to waiting passengers on Sunday afternoon.
A Heathrow spokesman said: “The shuttle buses to the long-stay car park were impacted by congestion on the roads following an earlier incident which saw the Central Terminal Area tunnel closed for safety reasons.
“The buses are now operating as normal, and we apologise for any inconvenience caused.”
Rail passengers at Heathrow Terminal 2/3 station also faced long queues amid overcrowding.
Anyone with information about the incident is asked to call 101, quoting CAD 1803 7 DEC.
