With Lawmaker’s Killing, U.K. Confronts a New Episode of Terrorism

LONDON — Prime Minister Boris Johnson and other British leaders paid their respects on Saturday morning at a church east of London where a Conservative lawmaker was fatally stabbed a day earlier, as the country grappled with another apparent episode of lone-wolf terrorism.

A somber Mr. Johnson — joined by the opposition leader, Keir Starmer, and other officials — laid flowers outside the Methodist church in Leigh-on-Sea, a sleepy seaside community that was convulsed on Friday when the lawmaker, David Amess, was assaulted during a routine meeting with constituents.

The police arrested a 25-year-old man at the scene and said they were conducting searches at two locations in the London area. The Metropolitan Police formally declared the attack a terrorist episode, with a potential link to Islamist extremism, but they have not yet identified the man, who they said they believed acted alone. The BBC, citing government sources, reported that he was a British national who appeared to be of Somali heritage.

The brutal attack, at midday and in full view of the public, has stunned the British political establishment and fanned questions about the security of members of Parliament. Lawmakers regularly meet their constituents, unprotected, to hear their concerns and grievances in sessions — known as surgeries — that can at times become heated.

An attack outside such a session in 2016 killed Jo Cox, a Labour member of Parliament. Another, in 2010, left Stephen Timms, also a Labour lawmaker, seriously wounded after he was stabbed in the abdomen.

The stabbing of Mr. Amess has also rekindled memories of other attacks by radicalized individuals, most recently in February 2020, when a 20-year-old man with a history of extremism was shot and killed by the police after stabbing two pedestrians in South London.

That man, Sudesh Amman, had just been released halfway into a three-year sentence on charges of distributing extremist material and possessing material that could be useful for preparing a terrorist attack. He was being tailed by undercover police, who interrupted the daylight assault on a busy street.

In November 2019, the police shot and killed Usman Khan, 28, on London Bridge after he set off on a frenzied stabbing spree, killing two people and wounding three. Mr. Khan, the British-born son of Pakistani immigrants, had earlier been convicted of being part of a group that plotted to bomb London’s stock exchange.

In April, the Johnson government tightened terrorism laws, mandating that those convicted of serious acts of terrorism serve a minimum of 14 years in prison, under stricter supervision. Some legal critics argue that prolonging prison terms only serve to radicalize offenders even further.

As Scotland Yard scrambled for answers on Saturday, public officials paid tribute to Mr. Amess’s long record of government service.

Commissioner Roger Hirst of the Essex Police, which has jurisdiction over Leigh-on-Sea, said in a statement that it was “a somber moment of reflection to remember a man who worked so hard for his community, who served those he represented passionately and made a real difference for Southend.”

“As we try and come to terms…