The British public have been warned to expect long queues and be prepared to stand for many hours through the night as details are published on how they can attend the queen’s lying in state before the funeral on Monday.
By 8am on Wednesday — nine hours before the doors open — the line stretched to between Lambeth Bridge and Westminster Bridge.
It is thought the queue might eventually reach more than six kilometres up the Thames and beyond Tower Bridge towards Southwark Park in Bermondsey.
The queen's coffin will be placed in London’s Westminster Hall and people will be able to file solemnly past 24 hours a day from 5pm on Wednesday until 6.30am on the day of the funeral — Monday, September 19.
The government has stressed that the queue will move continuously — with little chance to rest or sit down — and the line of those waiting is expected to stretch through central London.
What are the rules for attending the queen's lying in state?
The government urged people to “dress appropriately for the occasion to pay your respects”, banning clothes “with political or offensive slogans”.
“Please respect the dignity of this event and behave appropriately. You should remain silent while inside the Palace of Westminster,” it added.
Queue-jumpers and anyone drunk will be removed by stewards and police patrolling the lines.
Visitors will also face airport-style security checks, with tight restrictions on what can be taken in.
Flowers, tributes, candles, flags, photos, hampers, sleeping bags, blankets, folding chairs and camping equipment are all banned, with only one small bag with a simple opening or zip permitted for each person.
Where will the queen be lying in state?
Hundreds of thousands of people are flocking to the capital for the proceedings.
The queen’s closed coffin will rest on a raised platform, called a catafalque, in the ancient Westminster Hall in the Palace of Westminster, draped in the Royal Standard with the Orb and Sceptre placed on top.
Delays to public transport and road closures around the area are expected and people are being urged to check and plan accordingly.
“Please note that the queue is expected to be very long. You will need to stand for many hours, possibly overnight, with very little opportunity to sit down, as the queue will keep moving,” government guidance says.
It also asked people to think carefully about whether to take youngsters with them.
Details of the route for the queue will be published at 10pm on Tuesday, with full guidance on the gov.uk website.
The queue may close early to ensure as many visitors as possible can enter before the lying in state period comes to an end.
Step-free and accessible options are available for those who need them.
What do people waiting say?
The overwhelming sentiment among those waiting was a need to pay their respects, with many saying they had never really considered themselves royalists.
Small friendship groups had started to form among those waiting, with people offering around their snacks and keeping an eye on their neighbours' bags so they could take comfort breaks.
Kate Paysen, 58, flew in from Lisbon for the lying in state. “My father was in the army and I grew up in a royalist household, and I think it's important to come and be part of history. I think the queen for me always made me feel proud to be British,” she said.
Gina Carver, from Tunbridge Wells, Kent, said: “To give up my day queuing is nothing compared to what she's done for 70 years — and she does feel like our grandmother. She was the face of reason, you always think things are going to be all right if she says it's all right.”
Helen Redding, from Sidcup, south-east London, said: “When the queen died I was shocked how much it meant to me. I felt like I had to be here, to be part of history and I didn't want to miss this opportunity to pay my respects.”
Rehearsals for the procession of Queen Elizabeth's coffin in London — in pictures
What to bring to Queen's lying in state?
Official guidance suggests that people should bring suitable clothing for the weather, food and drinks to have while queuing, a portable power bank for their mobile phone and any essential medication.
Only bags smaller than 40 centimetres by 30cm by 20cm will be allowed into the hall.
Larger bags can be left at the bag drop facility, but capacity is limited and waiting for a space will increase people’s queuing time, the guidelines stated.
Flasks or water bottles, except clear water bottles that must be emptied of their contents before the security search point, are prohibited inside, as are weapons, whistles, smoke canisters, air-horns and other such items.
The queen’s coffin will be guarded around the clock by units from the Sovereign’s Bodyguard, the Household Division, or Yeoman Warders of the Tower of London.
The ceremonial procession of the coffin to Westminster Hall will travel by Queen’s Gardens, The Mall, Horse Guards and Horse Guards Arch, Whitehall, Parliament Street, Parliament Square and New Palace Yard.
Members of the public can watch the procession at the ceremonial viewing areas along the processional route, or at a screening site in Hyde Park.
Viewing areas and the Hyde Park site will open at 11am on Wednesday and people will be admitted in order of arrival time.
Tributes will be left on site until all ceremonial activity has taken place and it is expected that flowers will be removed from park areas from seven to 14 days after the funeral.
Flowers that have deteriorated will be removed throughout and taken to the Hyde Park nursery for processing to prepare them for composting.