Panicked passengers fled
Device has hallmarks of earlier blast bids
Armed police gather near to Parsons Green station yesterday morning.
Forensic officers begin their search for clues at the crime scene. Mark Rowley, the country’s most senior counter-terrorism officer, said “many urgent inquiries” are ongoing.
He said: “We now assess this was a detonation of an improvised explosive device.”
Asked if it was clear whether the person responsible was on the train at the time, Mr Rowley said: “It’s very much a live investigation and we are following down the lines of inquiry.”
Mr Rowley said Londoners can expect to see an “enhanced police presence”.
The blast comes with the UK on high alert following four terrorist attacks so far this year.
Authorities have foiled 19 plots since the middle of 2013, including six since the Westminster atrocity in March.
The incident comes a day after figures showed terrorrelated arrests in Britain have hit a record high, with suspects held at a rate of more than one every day.
Police and MI5 are running 500 investigations involving 3,000 individuals at any one time, while 20,000 former “subjects of interest” are kept under review.
As of 5.30pm yesterday, NHS England said it was now treating 21 patients. Eight others were discharged earlier in the day.
The explosion occurred on an S-Stock train which can carry more than 800 passengers.
The S-Stock were the first Tube trains to have walkthrough carriages to boost capacity when they were introduced to the network in 2010. instead bore echoes of the case of Damon Smith, 20, who was jailed for 15 years in May after leaving a home-made bomb in a rucksack containing ball bearings on a Jubilee Line train.
Smith, who had autism and was not motivated by terrorism, created the bomb after finding an al Qaida guide online.
Mr Herrington said such guides could be found within “10 seconds” through search engines.
Chemistry expert Professor Hans Michels said there were similarities with the failed attempts to bomb the Tube on July 21 2005.
The Professor of Safety Engineering, from the Department of Chemical Engineering at Imperial College London, said: “In appearance and arrangement the remnants of the device seem highly similar to those of the hydrogen peroxidebased devices of 2005.
“The size of the device and its containment in a plastic bucket is also the same. The flash flame reported suggest the ‘explosion’ was only partly successful. In particular much of the bucket still seems to be intact and there appear to be no victims with lethal impact wounds.
“I must speculate the mixture was not of the right composition or the ignition system was inadequate or not properly placed. That much of the bucket is intact supports the latter possibility.”
The incident sparked a huge response from the emergency services.
A picture taken by a passenger shows a bucket on fire following the incident which police declared a terrorist attack.