POLICE have arrested an 18-year-old man in the port area of Dover in connection with the explosion on a London Underground train at Parsons Green on the District Line.
The improvised device was in a white container in a Lidl’s bag and it exploded towards the rear of the train.
NHS England confirmed that 29 casualties were treated in four hospitals.
Deputy Assistant Commissioner Neil Basu, Senior National Co-ordinator for Counter Terrorism Policing, said: “We have made a significant arrest in our investigation this morning. Although we are pleased with the progress made, this investigation continues and the threat level remains at critical.
“The public should remain vigilant as our staff, officers and partners continue to work through this complex investigation. We are not, at this time, changing our protective security measures and the steps taken to free up extra armed officers remain in place.
“This arrest will lead to more activity from our officers. For strong investigative reasons we will not give any more details on the man we arrested at this stage.”
Detectives from the Met’s Counter Terrorism Command are continuing to urge anyone with information about the terrorist attack to contact police.
Thirty people are known to have been injured during the attack in which an improvised explosive device was detonated on a tube train at Parsons Green Underground Station at around 08:20hrs on Friday, 15 September.
So far, detectives have spoken to 45 witnesses and continue to receive information from the public to the confidential anti-terrorist hotline.
The public has sent 77 images and videos to investigators via the UK Police Image Appeal website. Anyone with footage or images from the incident is urged to upload them at www.ukpoliceimageappeal.co.uk where they will be looked at by investigators.