CONSERVATIVE MP Sir David Amess has died after being stabbed multiple times at a church in Essex.
A man is understood to have walked into Belfairs Methodist Church and knifed the 69-year-old multiple times.
Armed cops swooped on the in Leigh-on-Sea church after the minister, who represents Southend West in Essex, was attacked at the meeting just after midday.
Police confirmed a suspect has been arrested and said they are not looking for anyone else.
Read our David Amess live blog for the latest updates
Counter terror police now leading investigation
The investigation into the fatal stabbing of Sir David Amess is being led by counter-terror officers, Essex Police have said.
The death has led to Home Secretary Priti Patel asking all police forces to review security arrangements for MPs "with immediate effect".
Chief constable Ben-Julian Harrington said 69-year-old Southend West MP Sir David was "simply dispensing his duties when his life was horrifically cut short".
A 25-year-old man has been arrested on suspicion of murder following the attack at Belfairs Methodist Church in Leigh-on-Sea near Southend at midday on Friday and remains in custody.
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."
Home Secretary orders immediate review MP's security
Home Secretary Priti Patel has ordered an immediate review of MPs' security following the killing of Sir David Amess while meeting constituents.
Ms Patel met police and representatives of the security and intelligence agencies after the 69-year-old MP was fatally stabbed as he held a surgery in his Southend West constituency.
A spokesman for the Home Secretary said that she had also spoken to the Commons Speaker Sir Lindsay Hoyle.
"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 said.
Earlier, Ms Patel said she was "devastated" by the loss of Sir David in what she described as an "attack on democracy itself".
Police appeal for information
Essex police, fire and crime commissioner Roger Hirst urged anyone with information about the killing of Sir David Amess to contact the police.
"This is a shocking and utterly despicable attack against somebody who was an outstanding MP and has worked tirelessly for their community for many, many years," he said in a statement outside Southend police station.
"I know from personal experience the passion with which he stood up for and represented this community. He had a big heart.
"It is vital that we give the police all our support to ensure that they can do their job at this time. For anybody who has information, please do not hesitate to contact the police."
Statement from Essex Police
In a statement Essex Police said: "A man has been arrested on suspicion murder after a man was stabbed in Leigh-on-Sea.
"We were called to an address in Eastwood Road North shortly after 12.05pm today.
"We attended and found a man injured. He was treated by emergency services but, sadly, died at the scene.
"A 25 year-old man was quickly arrested after officers arrived at the scene on suspicion of murder and a knife was recovered.
"He is currently in custody. We are not looking for anyone else in connection with this incident."
All four surviving PMs pay tribute
All four surviving former prime ministers also paid tribute to the long-serving MP.
Theresa May said his death was "heartbreaking" and "a tragic day for our democracy", adding: "A decent man and respected Parliamentarian, killed in his own community while carrying out his public duties."
David Cameron said it Sir David was "the most committed MP you could ever hope to meet", and said: "David Amess was a kind & thoroughly decent man. Words cannot adequately express the horror of what has happened today."
Tony Blair, who also became an MP for the first time in the 1983 election, said he was "horrified" by the attack, commenting: "Though on opposite political sides I always found him a courteous, decent and thoroughly likeable colleague who was respected across the House."
Sir John Major said: "This is truly heartbreaking news of a good and decent man who - for over 30 years - was a dedicated public servant. My heart goes out to his family."
'An attack on democracy'
Home Secretary Priti Patel has condemned the killing of Sir David Amess as an "attack on democracy", which raises renewed questions about the security of MPs.
Ms Patel expressed concern that 69-year-old Sir David was fatally stabbed while holding a constituency surgery in his Southend West seat.
His death 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 Patel said she was "devastated" by the loss of Sir David, who she described as a "kind and loyal friend".
"That he was killed while going about his constituency duties is heart-breaking beyond words. It represents a senseless attack on democracy itself," she said in a series of tweets.
"Questions are rightly being asked about the safety of our country's elected representatives and I will provide updates in due course."
Investigation to be led by counter-terrorism cops
The investigation into the fatal stabbing of Tory MP Sir David Amess will be led by counter-terrorism officers.
The development was confirmed by Essex Police chief constable Ben-Julian Harrington in a statement at Southend Police Station.
Sir David attack 'awful beyond words'
Scottish First Minister Nicola Sturgeon described the attack as "awful beyond words".
She said: "Elected representatives from across the political spectrum will be united in sadness and shock today.
"In a democracy, politicians must be accessible and open to scrutiny, but no-one deserves to have their life taken while working for and representing their constituents."
PM: Let police get on with investigation
When asked about whether the death of Sir David Amess, which comes only five years after the murder of Labour MP Jo Cox, highlights a problem with the security protection of MPs, Boris Johnson said: "I think what we need to do now is let the police get on with the investigation.
"I am sure that all those issues will be considered in the proper time but I think this is a moment for us to think of Sir David, his wife, his family and our thoughts are very much with them."
Boris Johnson: 'Our hearts are filled with shock and sadness'
BORIS Johnson tonight paid tribute to Conservative MP Sir David Amess who has died after being stabbed multiple times.
In a statement from No 10 the visibly shocked PM said the nation has lost "a fine public servant and a much loved friend".
Boris, who spent the day in Bristol with his Cabinet, said: "I think all our hearts are full of shock and sadness today. Sir David Amess was killed in his constituency surgery in a church after almost 40 years of continuous service to the people of Essex and the whole of the UK.
"The reason I think people are so shocked and saddened is above all he was one of the kindest, nicest, most gentle people in politics and he also had an outstanding record of passing laws to help the most vulnerable.
"David was a man who believed passionately in this country and in its future and we've lost today a fine public servant and a much loved friend and colleague. Our thoughts are very much today with his wife his children and his family."
David Amess shunned ministerial ladder to stay on backbenches
David Amess was part of a new gang of Tory grafters and strivers who reshaped their party forever.
And as such, Sir David shunned the ministerial ladder which proves simply too alluring for most politicians.
Instead, this proud Essex boy preferred to stay on the backbenches where he could freely speak his mind, and stand up for his constituents, without the muzzle of ‘collective ministerial responsibility’ which gags so many politicians.
His colleagues and friends remember a charismatic, witty and charming MP.
Priti Patel to give security update 'in due course
Home Secretary Priti Patel said she would provide an update "in due course" on questions around the safety of MPs following the death of Sir David Amess.
She said on Twitter: "Questions are rightly being asked about the safety of our country's elected representatives and I will provide updates in due course. My heartfelt thoughts and prayers are with David's family and friends."
Ms Patel added: "I am devastated we have lost Sir David Amess. David was not only a fellow Essex MP, but a kind and loyal friend.
"David served the people of Southend with endless passion, energy and integrity. That he was killed while going about his constituency duties is heartbreaking beyond words. It represents a senseless attack on democracy itself."
'A friend to everyone'
By Kate Ferguson and Natasha Clark
SIR David Amess, 69, was an Essex boy born and bred who served the people of his home county for nearly 40 years.
First elected to Parliament as a 31 year-old in 1983, he was one of the throng of new young, bright Thatcherites taking Britain politics by storm
"He was the embodiment of Essex man”, his friend and fellow Tory MP Robert Halfon told The Sun.
"He was just the most wonderful and kindest and funny and compassionate politicians that we were lucky enough to know in our lifetimes."
Sir David, a married father-of-five, spent a short stint as a primary school teacher in London’s East End and then a spell as a recruitment consultant.
But politics was his calling and by his early 30s the ardent Brexiteer was the proud MP for Basildon in Essex.
When did Sir David Amess become an MP?
Sir David Amess became an MP for Basildon in June 1983.
He continued to serve both as an MP and a local councillor until 1986.
In June 1995 he was selected for Southend West and returned to Westminster two years later.
During his career, he sponsored a number of parliamentary bills, with the most important being the Protection Against Cruel Tethering Act in 1988 and the Warm Homes and Energy Conservation Act in 2000.
He was a vocal supporter of Brexit in the 2016 EU referendum.
Since the referendum, he had been a supporter of the Leave Means Leave campaign.
Who is Sir David Amess's wife Julia Arnold?
Julia Arnold is the wife of David Amess.
She works as a part-time caseworker for her husband.
Little is currently known about her and her professional background.
DUP leader pays tribute to Sir David
DUP leader Sir Jeffrey Donaldson has conveyed his condolences to the family and friends of MP Sir David Amess, who has died following a stabbing.
"Our prayers are with those closest to David. This is shocking and horrendous," he said.
"Sir David Amess has been a long-standing friend to me personally but also to the Union. More than many in Westminster, he took a keen interest in Northern Ireland and its people. He always wanted to see the country moving forward.
"Such a brutal attack must be condemned and is a reminder of the dangers which still face people in public office."
Penny Mourdaunt remembers David Amess
Trade minister Penny Mordaunt has published a speech given by Sir David Amess at an event at the Royal Albert Hall.
She tweeted: "For those who didn't know Sir David Amess, this will give you a measure of the man.
"I'd played a small part in helping him get 200 children with learning disabilities to play the [email protected]
"This is the video I filmed on the night of his thank you speech."
Theresa May sends condolences to Sir David's family
Former Conservative prime minister Theresa May tweeted: "Heartbreaking to hear of the death of Sir David Amess.
"A decent man and respected Parliamentarian, killed in his own community while carrying out his public duties.
"A tragic day for our democracy. My thoughts and prayers are with David's family."