Members of the public hoping to see the Queen lying in state are being warned to expect long queues that could last overnight.
Authorities in London have issued guidance and rules on how to pay tribute to the monarch, when her coffin is brought to London before she is laid to rest.
For four days, the public will be able to file past the Queen’s closed coffin as it rests on a raised platform, called a catafalque, in the ancient Westminster Hall.
Her Majesty's coffin will be draped in the Royal Standard with the Orb and Sceptre placed on top.
Those wishing to pay their respects at London’s Westminster Hall will be able to file past 24 hours a day from 5pm on Wednesday, 14 September until 6.30am on the day of her funeral – Monday, 19 September.
Her Majesty's coffin arrives at Holyroodhouse in Edinburgh on Sunday
Hundreds of thousands of people are expected to flock to the capital for the once-in-a-lifetime occasion.
But the government has emphasised that the queues will be very long, will continuously move – with little chance to rest or sit down – and are expected to stretch throughout central London.
Authorities have also released rules regarding clothing, food, drinks, bag sizes and floral tributes, which those wishing to attend must abide by.
According to the official guidance published Monday, visitors will 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 will all be banned, with only one small bag per person permitted.
The official guidance 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 booted out of the queue by stewards and police patrolling the lines.
Delays to public transport and road closures around the area are expected and people are being urged to check ahead and plan accordingly, and should be prepared for their journeys to take longer than usual.
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“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 stated:
It also asked people to think carefully about whether to take youngsters with them.
“Please consider this before you decide to attend or bring children with you,” it added.
Details of the route for the lying-in-state queue will be published at 10pm on Tuesday September 13.
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.
Aircraft banned from low altitude flying
Aircraft have been banned from flying over both London and Edinburgh at certain altitudes during the Queen's coffin procession - although commercial planes won't be affected.
The Civil Aviation Authority said the ban has been enforced as part of wider security arrangements. They said this will create a “protective blanket” over the restricted areas, but will not affect commercial flights because they operate above the altitude limits.
Aircraft are not permitted to fly below 2,500 feet above mean sea level within central London until 7am on September the 19th.
They have also been banned from flying below 6,000 feet above mean sea between Balmoral Castle in Aberdeenshire and the Palace of Holyrood in Edinburgh until just before midnight on Wednesday.
See the timetable of planned official events in the historic days ahead
The public have been warned the queues could take so long people may need to be prepared to stay overnight.
Security will be extremely tight, with very specific rules around what you can take.
The Palace of Westminster will have airport-like security and you will only be allowed to take one small bag, measuring no larger than 40cm x 30cm x 20cm, inside with you.
Larger bags can be left at the bag drop facility, but capacity is limited, it may be full, and waiting for a space will increase people’s queuing time, the guidelines stated.
Watch the Queen's final journey through Scotland
Food or liquids will be banned inside, except for water in a clear bottle.
Flasks and all other non-clear water bottles must be emptied of their contents before the security search point, and are prohibited inside - as are weapons, whistles, smoke canisters and air-horns and other such items.
Floral tributes will also not be allowed inside, with dedicated areas outside the building being established for people to leave them instead.
Phones will also need to be put on silent mode, and people will be asked to keep noise to a minimum.
Asking someone to queue for you to hold your place will also be banned.
Where can I watch the Queen's coffin's procession?
The ceremonial procession of the coffin through central London to Westminster Hall on Wednesday, 19 September, 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.
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.
What is lying in rest?
Lying in rest describes the period between dying and being buried - or laid to rest.
A period of lying at rest can allow time for mourners to visit to pay tribute, and for time to arrange for a funeral.
The government has announced a bank holiday on the day of the Queen's funeral.
What is lying in state?
Lying in state is a formality in which a closed coffin is placed on view, allowing the public to pay their respects to the sovereign before their funeral ceremony.
The Queen's coffin will rest on a raised platform - known as a catafalque - in the middle of Westminster Hall, where it will be guarded 24 hours a day.
The tradition stretches back to the 17th century when Stuart sovereigns lay in state for a number of days.