Tributes have continued to pour in for Tory MP Sir David Amess after his tragic murder on Friday.
Counter-terrorism officers are leading the investigation into the killing of the pro-life Catholic MP, who was stabbed to death at the Belfairs Methodist Church in Leigh-on-Sea while holding a local constituency surgery.
A 25-year-old man was arrested at the scene and a knife recovered.
The Metropolitan Police have declared it a 'terrorist incident'.
A prayer released by the Methodist Church following the tragedy speaks of the "cost" paid by "those who give their lives to public service".
Sir David had been Conservative MP for Southend West since 1997 and an elected MP since 1983. He is survived by wife Julia and their five children.
Stunned locals gathered for a vigil at St Peter's Roman Catholic Church on Friday evening where Father Jeffrey Woolnough remembered him as someone with "that great east London spirit of having no fear and being able to talk to people at the level they're at".
"Have you ever known Sir David Amess without that happy smile on his face? Because the greeting he would always give you was always that happy smile," he said, according to the BBC.
Home Secretary Priti Patel has ordered an urgent review of MPs' security following his death, which has sparked an outpouring of grief from politicians and Church leaders.
Prime Minister Boris Johnson called Sir David "one of the kindest, nicest, most gentle people in politics", who had "an outstanding record of passing laws to help the most vulnerable".
"All our hearts are full of shock and sadness today," he said.
Labour leader Sir Keir Starmer said it was a "dark and shocking day".
"David had a profound sense of duty that I witnessed first-hand in parliament," he said.
Catholic leader Cardinal Vincent Nichols said Sir David's death was "a painful loss in so many lives" and that he would be praying for his loved ones and constituents.
"This death throws a sharp light onto the fact that our Members of Parliament are servants of the people, available to people in their need, especially in their constituencies," he said.
This horrific attack, as David was undertaking his constituency surgery, is an attack on our democratic process and traditions."
Sir David was a committed Catholic who in 2006 established the All-Party Parliamentary Group for relations with Holy See Group, and was involved in the 2010 visit of Pope Benedict to the Houses of Parliament.
"David carried out his vocation as a Catholic in public life with generosity and integrity," Cardinal Nichols continued.
"He served in Parliament for four decades and was respected by all political parties across the House. His untimely death is a great loss."
Lord Alton, a Catholic crossbench peer and good friend of the MP, said he had received news of Sir David's death with "profound sorrow".
"Notwithstanding all the good in the world we still have the capacity to do truly evil things," he said.
"This horrific attack has not only robbed David of his life but its reverberations will have devastating consequences for his family and loved ones. My thoughts are with Julia and their children. May he now rest in peace."
The Archbishop of Canterbury Justin Welby said Sir David's "deep faith fuelled his sense of justice".
"The murder of an MP, in the course of caring for their constituents, is a deep blow to this country, its citizens and everyone who desires a peaceful and flourishing democracy," he said.
"The only antidote to violence and hatred is love and unity. In this horrific and tragic moment we must come together, across political difference, and be the light that refuses to be cowed by darkness."
The Archbishop of York, Stephen Cottrell, said it was hard to make sense of the "horror" of Sir David's death.
"I had the great honour of calling David Amess a friend when I was Bishop of Chelmsford," he said.
"He was the MP for the constituency where I grew up, and not only did he always faithfully serve those people and that place, but had a particular concern for the Christian community born of his own deeply held Christian faith as a member of the Roman Catholic community.
"It is shocking that someone so dedicated to his community and public service was the victim of such violence as he went about his elected duty."
Coptic Orthodox Archbishop of London, Arcbishop Angaelos, said it was "a sad day when a person of the commitment and calibre of Sir David Amess is fatally attacked while faithfully fulfilling his duty to his constituents".
Andy Flannagan, Executive Director of Christians in Politics, said, "There are moments that hold up a mirror to the reality of who we are as a society. This tragic killing of another public servant may well be one of those.
"Are we again exposed to the extreme version of the lazy antipathy that so many of us indulge towards those who answer the call to public leadership?"