2017 Parsons Green bombing

On 15 September 2017, at around 8:20 am BST (07:20 UTC), an explosion occurred on a District line train at Parsons Green Underground station, in London, England. Thirty people were treated in hospital or an urgent care centre, mostly for burn injuries, by a botched crude 'bucket bomb' with a timer containing the TATP explosive chemical. Police arrested the main suspect, 18-year-old Iraqi refugee Ahmed Hassan in a departure area of the Port of Dover the next day, and subsequently raided several addresses including the foster home of an elderly couple in Sunbury-on-Thames where Hassan had lived. The incident is being treated by the Metropolitan Police as a terrorist attack and reported by the Press Association as being linked by investigators to Islamic extremism.

Background
Several attacks occurred in Britain in the months preceding the bombing. These include the Westminster attack, the Manchester bombing, the London Bridge attack and the Finsbury Park attack. According to the BBC home affairs correspondent Dominic Casciani, along with the Parsons Green bombing and police having foiled at least seven 'significant plots', this makes it "the most sustained period of terror activity in England since the IRA bombing campaign of the 1970s."

Incident
A homemade bomb partially exploded on an eastbound District line train at Parsons Green Underground station, in West London. The District line train was packed with commuters and school children. Witnesses described seeing a fireball in the rear carriage of the packed rush-hour train. Numerous passengers were reported to have suffered flash burns. Others received crush injuries in the rush to leave the scene. Thirty people received medical treatment for their injuries, 19 of whom were taken to hospital by ambulance and the remainder self-presenting at hospital.

The device had been left in a white plastic bucket inside a shopping bag. Wires were hanging out, as well as a black towel. Reports also indicate the device had a timer attached and was packed with knives and screws. According to Ben Wallace, the security minister, the bomb contained the triacetone triperoxide explosive (TATP), the same explosive used in the 2005 London Underground bombings and the November 2015 Paris attacks. The explosive is known to be very unstable, which may have led to critical errors in the construction of the bomb, such that it only partially exploded. According to Chip Chapman, former head of counter-terrorism at the Ministry of Defence, "This absolutely didn't function properly because… 1 oz of TATP is enough to blow car doors off".

Claim of responsibility
According to the Amaq News Agency, an affiliated unit of the Islamic State of Iraq and the Levant carried out the attack. The Metropolitan Police described the claim as "very routine in these sort of circumstances… whether or not they have had any previous engagement with the individuals involved". On 17 September Home Secretary Amber Rudd said there was no evidence to suggest ISIS was behind the attack, and added that they would find out how the attacker was radicalised if they could.

Investigation
British Transport Police are leading the investigation into the attack. According to the Metropolitan Police, “hundreds of detectives” are involved in the investigation. Investigators reportedly linked the attack to Islamic extremism. The Metropolitan Police launched a manhunt for one, possibly two, suspects.

On 16 September, Kent Constabulary arrested an 18-year-old male in the Port of Dover on suspicion of a terror offence. The port area was partially evacuated and a number of items recovered by the police. Later that day, police raided, and searched a house in Sunbury, Surrey. The 18-year-old is believed to be an Iraqi orphan refugee. Before the attack the 18-year-old suspect had been referred to a governmental anti-extremist programme.

Police also arrested a 21-year-old man on 16 September in Hounslow, west London, and were searching a house in Stanwell, Surrey, in connection with the attack. The 21-year-old was a Syrian refugee originally from Damascus, who arrived in the UK about 2013.

Both men arrested on 16 September had been cared for by the same foster carers. Their house, where both men had lived, is one of the properties in Surrey searched by police. The other one in Stanwell is where the 21-year-old lived after he left foster care. The two initial suspects were arrested on 16 September under Section 41 of the Terrorism Act and on 18 September police were granted a warrant to hold them for further questioning.

A third man, a 25-year-old, was arrested in Newport, south Wales, on 19 September and an address in Newport was searched.

On 21 September the 21-year-old was released without charge.

On 23 September 2017, the 18-year-old appeared in court charged with attempted murder and causing an explosion likely to endanger life or cause serious injury. He was remanded in custody and is due to appear at the Old Bailey on 13 October.

A seventh man, a 20-year-old, was arrested on 25 September in Cardiff.

Six of the seven men arrested have since been released without charge.

Domestic
In a statement after the incident, British Prime Minister Theresa May said: "My thoughts are with those injured at Parsons Green and the emergency services who, once again, are responding swiftly and bravely to a suspected terrorist incident". Mayor of London Sadiq Khan said: "As London has proven again and again, we will never be intimidated or defeated by terrorism. I am in close contact with the Metropolitan Police, Transport for London (TfL), Government and other emergency services who are responding at the scene and leading the investigation. I will be attending the emergency COBRA meeting in Whitehall this afternoon with the Prime Minister. My sincere gratitude goes to all our courageous emergency responders and the TfL staff who were first on the scene. I urge all Londoners to remain calm and vigilant". Khan also said: "I am not going to apologise for saying we need more resources and more police in London".

Subsequent to the attack, the Joint Terrorism Analysis Centre decided to raise the terror threat level from 'Severe' to 'Critical', for only the fourth time since its 2006 introduction. Operation Temperer was also activated for the second time, as a result of the raise in threat level. The terror threat level was then returned to 'Severe' by JTAC on 17 September 2017.

Citing the Parsons Green bombing, police advised the public not to record terrorist events, but instead to "run, hide, tell".

International
US President Donald Trump tweeted: “Another attack in London by a loser terrorist. These are sick and demented people who were in the sights of Scotland Yard. Must be proactive!” He also touted his proposed travel ban. His comments were described by Theresa May as “not helpful” and characterised the tweets as inaccurate speculation.