The Commons benches were packed as MPs stood with their heads bowed to take part in a minute of silence in a touching and stirring tribute at midday. MPs were dressed in all black as they gathered in a sombre atmosphere to pay their respects to the late Queen.
“We have witnessed the most heartfelt outpouring of grief”, Ms Truss said as she addressed MPs.
“In the hours since last night’s shocking news, we have witnessed the most heartfelt outpouring of grief at the loss of Her late Majesty the Queen.
“Crowds have gathered, flags have been lowered to half-mast, tributes have been sent from every continent around the world.”
She added: “On the death of her father King George VI, Winston Churchill said the news had stilled the clatter and traffic of 20th century life in many lands.
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“She knew this generation of Britons would be as strong as any.”
Regular business in the House of Commons has been suspended for the next 10 days as a mark of respect during the official mourning period.
MPs are instead meeting to share their stories and memories of the woman who spent the last 70 years on the throne.
Following Ms Truss’s lead, Sir Keir described the Queen as being “at the heart of this nation’s life”.
He said: “She did not simply reign over us, she lived alongside us, she shared in our hopes and our fears, our joy, and our pain. Our good times and our bad.”
The SNP’s Ian Blackford described the Queen as “one of the true constants in all our lives”.
Unusually, the Commons will sit again over the weekend when tomorrow senior MPs will take an oath of allegiance to the King from 2pm before condolences continue.
The Saturday siting will end with a “formal humble address” to the King, “expressing the deep sympathy of the House” following his mother’s death at Balmoral on Thursday, the House of Commons said in a statement.
Today also marked Boris Johnson’s first speech in the House of Commons since stepping down as Prime Minister at the start of the week.
Sat just a few seats away from his predecessor, Theresa May, he spoke of his last meeting with the monarch at Balmoral Castle on Tuesday.
He said she was “as radiant and as knowledgeable and as fascinated by politics as ever”.
He added: “That impulse to do her duty carried her right through into her 10th decade to the very moment in Balmoral.”
In her tribute, Ms May had the whole House of Commons laughing as she shared an anecdote about one of her meetings with the Queen.
Recalling setting the table for a picnic at Balmoral, she said: “I picked up some cheese, put it on a plate and was transferring it to the table. The cheese fell on the floor. I had a split-second decision to make.”
Mrs May paused as MPs burst into laughter, before adding: “I picked up the cheese, put it on the plate and put it on the table. I turned round to see that my every move had been watched very carefully by Her Majesty the Queen.
“I looked at her. She looked at me and she just smiled. And the cheese remained on the table.”
The tributes took place just 24 hours after many MPs first learnt of the Queen’s ill health in the Commons, with Speaker Sir Lindsay Hoyle reading out a short statement informing those present that doctors were “concerned”.
Ms Truss was informed of the developing situation just a few minutes before.
The Chancellor of the Duchy of Lancaster, Nadhim Zahawi, came into the Chamber and sat down next to the Prime Minister to begin urgently briefing her.
Sir Keir Starmer was also passed a note by his deputy Angela Rayner.