A memorial service for Sir David Amess has been held at St Margaret’s Church in Westminster
Addressing the congregation, which included around 800 of Sir David's colleagues, the Archbishop of Canterbury described him as "of the best"
The Archbishop of York remembered his "ability to listen" and "determination to help"
Earlier, Boris Johnson paid tribute in the Commons and announced Southend-on-Sea would become a city
Sir David campaigned tirelessly to gain that recognition for the town
MPs have been sharing memories of their former colleague in Parliament, with the PM describing him as a “steadfast servant”
Sir David, 69, was meeting constituents in his Southend West seat when he was fatally stabbed on Friday
A 25-year-old man was arrested at the scene and is being questioned by police
More laughter and cheering erupts in the chamber as Boris Johnson announces that the Queen has agreed Southend will be granted city status in honour of Sir David.
Sir David "never once witnessed any achievement by any resident of Southend that could not somehow be cited in his bid to secure city status for that distinguished town", says Johnson.
Laughter ripples through the House of Commons as the PM highlights some of Sir David's notable causes.
"Behind the famous and irresistible beam there lay a seasoned campaigner of verve and grit," he says.
This was whether he was demanding freedom for the people of Iran or counting votes for the Westminster Dog of the Year contest - whether he was battling Brexit or fighting his way to the front of the parliamentary pancake race, the PM says.
Sir David offered friendship and support to new members of all parties, Johnson says.
It was his determination to make this country a better place that inspired his "outstanding record" on behalf of the vulnerable and the voiceless, he says.
He adds that Sir David passed legislation on issues as diverse as animal welfare, food poverty and the registration of driving instructors. And he helped children with learning difficulties and women with endometriosis.
Boris Johnson says the House of Commons mourns alongside Sir David's family and they hold them in their hearts.
"Nothing I or anyone else can say will lessen the pain, the grief, the anger they must feel at this darkest of times," he says.
He says he will not allow the manner of Sir David's death to detract from his accomplishments as a politician or as a human.
"The last 72 hours has done little to numb the shock and sadness we all felt when we heard of the tragic and senseless death of Sir David Amess," says the prime minister.
Opening the tributes, Boris Johnson says the House has lost a steadfast servant and dear friend and colleague.
Sir David's wife Julia and their children have lost a loving husband and devoted father, he adds.
Prime Minister Boris Johnson is now opening the tributes to the late Conservative MP for Southend West in Essex, Sir David Amess.
Stay with us as we bring you more tributes from MPs and memories of the man the PM has called "one of the kindest, nicest, most gentle people in politics".
With Home Office questions ongoing, Home Secretary Priti Patel says the whole country is "horrified and shaken by the dreadful killing" of Sir David Amess and "utterly devastated" for his wife, family and loved ones.
She says Sir David had a huge number of friends in the House of Commons and in the community he served.
The causes he supported were diverse, she says, adding that so many related to people and animals, as well as his calls for city-status for his Southend constituency.
He conducted politics in a "civilised but good humoured way" that "came naturally" to him, she adds.
"Decency ran through him like the writing in a stick of Southend rock," she concludes.
This is the moment the speaker's chaplain began a minute's silence to honour Sir David Amess.
The House of Commons is packed as MPs gather to pay tribute to Sir David Amess.
The mood was sombre as they filed into the chamber following the mace - a symbol of parliamentary authority - on their return from recess.
A special session will start at 15:30 BST for MPs to pay their respects and share memories of their late colleague.
We will bring you updates from that session here, and you can also watch it live via the stream at the top of this page.
In the House of Commons, shadow Home Office minister Jess Phillips pays tribute to Sir David Amess, sending Labour's "love and best regards" to his family.
"He was kind and good, but for me, above all else, he was funny," she adds. "He didn't take himself too seriously."
Susan Hulme
Parliamentary correspondent
MPs were expecting to return to Westminster after the three week party conference recess to discuss all the big issues of the day - the cost of living, supply chain problems, fuel prices.
But instead, there was no politics.
Just a sad and shocked Commons chamber, as MPs stood together, absorbing the reality that another of their number had been killed while going about their constituency business.
The Speaker's Chaplain, Rev Tricia Hillis, announced a minute's silence asking that the "bright memory" of Sir David Amess's rich life "ever outshine the tragic manner of his death".
The division bell rang. And MPs stood - sombre and with heads bowed.
BBC Radio 5 Live
Image source, PA MediaA caseworker for former Liberal Democrat leader Tim Farron is calling for stab vests to be issued to MPs and their staff.
Speaking in the wake of the killing of MP Sir David Amess, Jude Godden, who has worked for Westmorland and Lonsdale MP Tim Farron for six years, says: "At times you don't feel safe."
She says "nothing prepared her" for the abuse she would see working for the ex-Lib Dem leader.
She tells BBC Radio 5 Live she first raised the issue of stab vests after the murder of MP Jo Cox in 2016 with the Independent Parliamentary Standards Authority (IPSA) but nothing came of it.
She says decision makers in London were "not in touch" with the types of venues used by MPs to hold their regular constituency surgeries in, such as community centres, village halls and churches.
"If anybody is going to be attacked it's most likely to be a knife attack," she adds.
Labour MP Chris Bryant - himself the recipient of a death threat over the weekend - says we seem to have developed a toxic way of doing our politics and asks how can that be changed so people behave a bit more like David Amess and James Brokenshire.
Home Secretary Priti Patel responds by saying everyone has a responsibility to work together and the key word going forward should be "respect".
Home Office questions have just started in a packed House of Commons and will last until a special session begins at 15:30 BST, where MPs will give their tributes to Sir David Amess.
Priti Patel opens by paying tribute to the Conservative backbencher and says everyone is thinking of his family.
She also pays tribute to former minister, James Brokenshire, who died of lung cancer recently while the House was in recess.
Image source, Parliament TVA minute's silence has been held in the House of Commons in memory of Sir David Amess.
Speaker Sir Lindsay Hoyle led a procession of MPs into the chamber for the opening of the new session and the House stood with heads bowed.
The Speaker's chaplain, Tricia Hillas, told the chamber: "May the bright memory of his rich life ever outshine the tragic manner of his death."
All parliamentary business will be paused for MPs to remember Sir David from 15:30 BST.
There's due to be a minute's silence in the House of Commons at around 14:30 BST, in memory of Sir David Amess.
After that, there will be Home Office Questions, followed at 15:30 by tributes to Sir David.
Image source, PA MediaWhen MPs pay tribute to Sir David Amess at 15:30 BST, there is likely to be discussion of his extensive campaigning over the decades.
The cause he was best known for - and which he mentioned on many occasions in the House of Commons - was giving his home town of Southend city status. This, Sir David argued, would boost the area's prosperity and standing.
The Southend West MP was also an animal rights activist who supported Labour's ban on fox hunting.
He was an early and consistent supporter of Brexit, campaigned against fuel poverty and advocated more action to tackle obesity.
And Sir David worked to raise awareness of endometriosis, a painful condition of the womb.
The family of Sir David Amess have visited the church where he was killed and seen some of the many tributes left in his memory.
Sir David's widow, Julia, was comforted by family members as she read messages during the 10-minute visit to Belfairs Methodist Church in Leigh-on-Sea.
As we reported earlier a man has been arrested after Labour MP Chris Bryant reported receiving a death threat following the killing of Sir David Amess.
The MP for Rhondda says that MPs probably report fewer threats to the police than they should as they are "all too aware of how overstretched" police forces are.
Sir David Amess: 'MPs probably report less than we should' - Chris Bryant
Image source, Getty ImagesLabour MP Tulip Siddiq says being an MP has had a "constant effect" on her family since she was first elected in 2015.
Abuse received online can "range from very trivial things", such as comments on her appearance, to threats against her or her relatives, she tells the BBC.
The Hampstead and Kilburn MP recalls the murder of fellow Labour MP Jo Cox in 2016 and says her own mother called her immediately after hearing an MP had been attacked "because her first thought was it must have been me".