One year ago today, on September 15, 2017, at just past 0800 local time, a bomb exploded at London’s Parsons Green Underground train station. The blast injured thirty people. 18-year-old Ahmed Hassan was arrested the next day at the Port of Dover. Hassan, an Iraqi, arrived in the United Kingdom illegally in October 2015.

Although the bombing was claimed by Daesh (ISIS), Amber Rudd, British Home Secretary, stated there was no evidence supporting the terrorist group’s claim. The London Metropolitan Police added that the claim was “very routine in these sort of circumstances”.

The bomb itself was described as being a crudely assembled homemade bucket bomb containing the explosive chemical triacetone triperoxide (TATP). The crudeness of its construction is evident in the fact that it only partially exploded.

The bomb was in a plastic bucket in a shopping bag. Some reports stated the explosive had a timer attached and that wires were hanging out.

TATP is known to be very volatile. This lends it to be not only very sensitive to work with, but also highly destructive. According to former head of counter-terrorism at the British Ministry of Defence, Chip Chapman, “This absolutely didn’t function properly because… 1 ounce (30 g) of TATP is enough to blow car doors off”.

National political response was as forthright as you might expect, expressing both compassion and solidarity. 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”. Further, the Mayor of London, Sadiq Khan stated, “As London has proven again and again, we will never be intimidated or defeated by terrorism.”

As a result of this bombing, the United Kingdom’s Joint Terrorism Analysis Centre (JTAC) increased the terror threat level to ‘Critical’. Operation Temperer, a British government plan to deploy troops in support of police operations following a terrorist attack, was also reactivated. The JTAC returned the terrorist threat level to ‘Severe’ two days after the attack.

International political response from United States President Donald Trump came in the form of a tweet: “Another attack in London by a loser terrorist…”

In the legal aftermath, Hassan pleaded not guilty to all the charges. His trial took place in March of 2018. On March 16, a unanimous jury found him guilty of all charges. His sentencing took place the following week.  On March 23, Ahmed Hassan was sentenced to life imprisonment, serving a minimum of 34 years. He will be eligible for parole in 2052.