A review of MPs’ security has been ordered following the death of Conservative MP David Amess, who was fatally stabbed while meeting constituents.
Official sources told the PA news agency that a 25-year-old man arrested on suspicion of murder is believed to be a British national with Somali heritage.
The death of Mr Amess – which is being investigated by counter-terror officers – has led to UK Home Secretary Priti Patel asking all police forces to review security arrangements for MPs “with immediate effect”.
The Commons Speaker Lindsay Hoyle said on Friday that police are contacting all MPs to check on their security.
The man arrested following the attack at Belfairs Methodist Church in Leigh-on-Sea near Southend at midday on Friday remains in custody.
Chief constable of Essex Police Ben-Julian Harrington said 69-year-old Southend West MP Sir David was “simply dispensing his duties when his life was horrifically cut short”.
Tory veteran Mr Amess, who was described by UK Prime Minister Boris Johnson as “one of the kindest, nicest, most gentle people in politics”, had been an MP since 1983 and was married with five children.
Mr Harrington said: “The investigation is in its very early stages and is being led by officers from the specialist counter-terrorism command.
“We made it clear at the time of the incident that we did not believe there was any immediate further threat to anyone else in the area.
“It will be for investigators to determine whether or not this is a terrorist incident, but as always they will keep an open mind.”
Meanwhile, Ms Patel met police and representatives of the security and intelligence agencies after the stabbing, which took place as Sir David held a surgery in his Southend West constituency.
“The Home Secretary has asked all police forces to review security arrangements for MPs with immediate effect and will provide updates in due course,” the spokesman for Ms Patel said.
The Daily Telegraph said the review will look at Operation Bridger, a nationwide police protective security operation, which was set up in 2016 in the wake of a number of threats to MPs following Parliamentary debates on Syria.
Ms Patel will make a statement to Parliament on the review on Monday, The Times reported.
The attack on Sir David came just five-and-a-half years after Labour MP Jo Cox was killed by a far right extremist in her Batley and Spen constituency in West Yorkshire.
Ms Lindsay said police are contacting all MPs to check on their security in the wake of Sir David’s killing.
“It is about doing the right things working with the police constabularies right across the United Kingdom because it is about joining that up,” Sir Lindsay told BBC2’s Newsnight.
“I know that they are contacting all the MPs to check about their safety, to reassure them, because in the end we have got to make sure that is a priority.”
He added: “Those people who do not share our values or share democracy, they will not win and we won’t let them win. We will continue to look at security, that is ongoing and it will continue.”
Sir Lindsay said earlier that while it was right that security was reviewed following the latest incident, it was important to avoid “knee-jerk” reactions.
He told BBC Radio 4’s PM programme: “What we want to do is make sure MPs can carry out their duties. We have got to make sure MPs are safe.”
His sentiments were echoed by the the Father of the House – the longest-serving sitting MP – Sir Peter Bottomley.
“I predict all over the country this weekend, next weekend and in the months to come MPs will hold advice sessions. That is what we do,” he told the PA news agency.
“There is no perfect security for anybody. My view has always been that in many other walks of life you are at far greater risk than a Member of Parliament.
“MPs may get exceptional publicity. We are not exceptional people. We’re ordinary people trying to do an ordinary job as well as we can. We accept the risks.
“The question is should MPs stop meeting their constituents face-to-face. The answer is we will go on meeting our constituents face-to-face.”