Queues to see the Queen’s lying in state could last 12 hours and stretch for miles, with mourners warned to be prepared to stand for many hours through the night.
The public will be able to pay their respects to the late monarch’s coffin in London’s Westminster Hall 24 hours a day from 5pm on Wednesday 14 September until 6.30am on the day of the funeral, Monday 19 September.
Hundreds of thousands of people are expected to flock to the capital for the once-in-a-lifetime proceedings.
The Government has set out guidelines for those who are preparing to visit London to pay their respects, including how people should behave and what they should wear.
What are the Government’s guidelines?
The Government has urged people to “dress appropriately for the occasion to pay your respects”, banning clothes “with political or offensive slogans”.
Guidance states: “Please respect the dignity of this event and behave appropriately.
“You should remain silent while inside the Palace of Westminster.”
Queue-jumpers and anyone who is drunk will be booted out of the queue by stewards and police patrolling the lines.
Visitors will also face airport-style security checks, with tight restrictions on what can be taken in.
The guidance adds: “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.”
Members of the public are also asked to think carefully about whether to take children with them.
Flowers, tributes, candles, flags, photos, hampers, sleeping bags, blankets, folding chairs and camping equipment are all banned, and flowers should only be taken to the dedicated area in Green Park.
Only one small bag with a simple opening or zip is permitted per person.
Details of the route for the lying-in-state queue will be published at 10pm on Tuesday 13 September, with full guidance on the Government 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.
What are you allowed to bring?
Official guidance suggests that people should bring suitable clothing for the weather, food and drinks to have while queueing, a portable power bank for their mobile phone and any essential medication.
Only bags smaller than 40cm x 30cm x 20cm will be allowed into the hall. Larger bags can be left at the bag drop facility, but capacity is limited and it may be full - waiting for a space will increase people’s queuing time.
Flasks or water bottles, except clear water bottles which must be emptied of their contents before the security search point, are prohibited inside, as are weapons, whistles, smoke canisters and air-horns and other such items.
Government guidance says people should not film, photograph, use mobile phones or other handheld devices in the security search area or within the Palace of Westminster.
What can people expect to see?
The Queen’s closed coffin will rest on a raised platform, called a catafalque, in the ancient Westminster Hall in the Palace of Westminster.
It will be draped in the Royal Standard with the Orb and Sceptre placed on top.
A priceless crown and other regalia are traditionally placed on top of a sovereign’s coffin.
The Queen’s coffin will be guarded around the clock by a vigil of units from the Sovereign’s Bodyguard, the Household Division, or Yeoman Warders of the Tower of London.
It is likely that the Queen’s children or even grandchildren will honour her with a vigil and join the guard over the coffin at some point – a tradition which has been called the Vigil of the Princes.
Should the Princess Royal stand guard for the Queen, she will be the first female member of the royal family to do so.
What has been said about London traffic?
Whitehall chiefs in charge of logistics for the historic five-night vigil have estimated mourner numbers could be close to that which turned up to view Pope John Paul II, according to The Sun.
A million mourners filed past the late pope when he lay in state in Rome in 2005.
The Rail Delivery Group has warned those wanting to travel to Westminster Hall to expect services to London and all of its stations to be “extremely busy”.
The rail operator’s customer information director told the BBC people needed to plan carefully and allow plenty of time if planning to travel during the official mourning period.
Transport for London also warned that roads and public transport in central London will be very busy and has advised travellers to allow “plenty of extra time” for their journeys and to avoid driving where possible.
Andy Byford, London’s Transport Commissioner, told the BBC: “We are working with our partners to keep our city moving smoothly and to ensure that everyone who is planning to attend the memorial events can do so safely.”
Where can you watch the procession in London?
The ceremonial procession of the coffin to Westminster Hall will travel via 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.