Brits have been told not to set off to queue for the Queen's lying-in-state - with the line set to close imminently as those at the end face a 13.5 hour wait.
The government is monitoring the situation and will provide an official cut-off point for people hoping to join, with public viewing set to close at 6.30am tomorrow.
A minute's silence is scheduled as mourners face their last chance to see the Queen's coffin lying in state.
Long queues consistently over 12 hours have been recorded ever since the body of the late monarch was brought to London and the line is now set to close.
On Saturday morning, the online tracker set up by the Department for Digital, Culture, Media and Sport (DCMS) estimated waiting times were over 25 hours.
They said: "We are monitoring numbers closely. Some people will unfortunately miss out."
The government source added: "We don’t want people to make long journeys only to find it closed. The public desire to view the Lying-in-State has been phenomenal."
"We will give people as much notice as possible so they can avoid disappointment."
The official cut-off time for people hoping to see the coffin of the monarch is 6.30am on Monday morning.
"We have always said we will need to close the queue well in advance of the Lying-in-State ending."
As the queue for Westminster Hall closes, The Queen Consort will lead a tribute to the Queen and her 70-year reign, before a country-wide minute's silence at 8pm.
She is expected to talk about the Queen's "wonderful blue eyes" and her smile while adding she "can't remember anyone except the Queen being there".
People have been recorded as coming in from all over the world to pay their respects, despite official warnings not to travel.
Deborah Alter, 62, flew from New York City to see the Queen lying in state.
She said: "When I told my daughter I was flying here she said, ‘You’re crazy!’, but I told her ‘I’ve got to go!’
"The Queen brought people together. I just loved her. She was one heck of a lady.” Deborah admitted she wept when she finally reached the coffin shortly after 11am yesterday."
Members of the public have been seen crying and bowing while celebrities like football star David Beckham joined the queue to pay their respects.
The former England captain said: "I thought by coming at 2am it was going to be a little bit quieter. I was wrong. Everybody had that in mind."
Elsewhere, a service of reflection in Falkirk will see 96 lanterns, one for each year of the late monarch's life, placed in the Queen Elizabeth II Canal in the city.
Wreaths will also be placed into the water, while Prime Minister Liz Truss is due to have an audience with the King before the new monarch hosts heads of state at Buckingham Palace.
On Monday, the Queen's funeral is scheduled to take place at Westminster Abbey in front of global audiences and a hall full of dignitaries including world leaders like US president Joe Biden and Emmanuel Macron of France.
Around 125 cinemas will screen the event across the UK, while the BBC, ITV and Sky News will have full coverage of the proceedings.
* You can now buy Friday's historic Daily Mirror commemorating the death of the Queen here: mirror.co.uk/commemorative
