Britain last night raised its security threat level to critical, the highest possible, as the bomber who caused an explosion on a packed London commuter train remained at large. Prime Minister Theresa May said armed soldiers would take over some police duties as security chiefs concluded that another attack may be imminent.
Twenty-nine people were injured when the bomb partially detonated on the District Line train at Parson's Green station in west London at 8.20am yesterday, at the height of the morning rush hour. Witnesses described scenes of panic as passengers sought to escape from a "wall of flame" created by the bomb, which was packed into a builder's bucket inside a Lidl supermarket bag.
Most of those injured, who included a boy aged around 10, suffered flash burns but some were hurt in a stampede in the station as passengers sought to flee. Police confirmed within hours that they were treating the incident as a terrorist attack caused by an improvised explosive device. The bomb, which is believed to have had a timer, appears to have failed to detonate fully.
Hundreds of detectives and intelligence experts were last night engaged in a massive counterterrorism investigation aimed at finding the bomber. Investigators were trawling through CCTV footage from the stations at which the train called before the attack but the Metropolitan Police last night dismissed a report that they had already identified a suspect.
The so-called Islamic State claimed responsibility for the attack but offered no evidence that the perpetrator was linked to the group.
The prime minister announced that the threat level had been raised to critical after the second meeting yesterday of the emergency Cobra committee. The threat level was last raised to critical, which means that the intelligence agencies believe an attack is imminent, after the Manchester Arena bombing in May, when it was lowered to severe after four days.
She said that the public could expect to see more armed police patrolling the streets and the transport network in the coming days.
“This is a proportionate and sensible step which will provide extra reassurance and protection while the investigation progresses,” she said.
Earlier, Ms May described as "unhelpful" a tweet from US president Donald Trump which suggested that the bomber was known to the British authorities.
“I never think it’s helpful for anyone to speculate on what is an ongoing situation. As I’ve said, the police and security services are working to understand the full circumstances of this cowardly attack and to identify all those responsible,” she said.
Parson's Green station remained cordoned off last night but residents in nearby buildings, who had been evacuated after the explosion, were allowed to return home after almost 12 hours. Chelsea football club announced extra security measures at their Stamford Bridge stadium near Parson's Green for a match on Sunday against Arsenal.
Friday's incident is the fifth terrorist attack Britain has suffered in the past six months. In March, Khalid Masood drove a car into pedestrians on Westminster Bridge, killing four, before stabbing to death a police officer in the Palace of Westminster and getting shot dead himself.
An explosion caused by suicide bomber Salmen Abedi at an Ariane Grande concert at Manchester Arena on May 22nd killed 22 and injured 250. On June 3rd, eight people died and 48 were injured when a white van drove into pedestrians on London Bridge and its occupants then went on a rampage in Borough Market, stabbing passersby before they were shot dead by police.
On June 19th, one man died and 10 were injured when a van drove into a group of people outside Finsbury Park mosque in London.