A man has been arrested after a 'potential hazardous materials incident' at London's Heathrow Airport on Monday saw 20 people injured.
The man, aged 57, was arrested on suspicion of possession of a firearm (CS spray) and causing a public nuisance on Tuesday, 9 September.
The Met Police said he remains in police custody at this time, and that the incident is not being treated as terrorism related.
Chaos broke out at Heathrow Terminal 4 shortly before 5pm on Monday, which emergency services later attributed to 'mass hysteria'.
Some 21 people reported being injured during the incident, but only one required hospital treatment.
