Mourners are expected to queue for hours day and night to see the Queen’s lying in state.

Waiting times to get into Westminster Hall are expected to be huge and queues could stretch back for miles.

Those travelling to London are advised to bring food and drink as well as suitable clothing.

Mobile phone usage will not be allowed in the hall, and there will be no photography.

The lying-in-state begins at 5pm on Wednesday and will last until 6.30am next Monday, which is the day of the Queen's funeral.

People will be able to file into the historic venue 24 hours a day.

The Rail Delivery Group has warned those wanting to travel to Westminster Hall to expect services to the capital 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 warns 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.

Whitehall chiefs in charge of logistics for the historic vigil estimate numbers could be close to the million mourners who turned up to view Pope John Paul II.

The last member of the Royal Family to lie in state in the hall was the Queen Mother 20 years ago.

More than 200,000 people queued to view her coffin, but many more are expected this week.

What is happening today?

King Charles III and the Queen Consort are to visit Westminster Hall in London where both Houses of Parliament will express condolences to the new monarch.

Later on Monday, Charles and Camilla will fly to Edinburgh where they will attend a Ceremony of the Keys and the King will inspect the guard of honour.

Charles will then lead the royal family in procession as the Queen’s coffin is taken from the Palace of Holyroodhouse to nearby St Giles’ Cathedral for a service of thanksgiving.

Members of the public will be able to view the coffin at the cathedral and pay their respects from 5pm for a period of 24 hours.

The King will then hold audiences with First Minister Nicola Sturgeon and Alison Johnstone, the Presiding Officer of the Scottish Parliament.

Later in the evening, the King and other members of the royal family will mount a vigil at the cathedral in honour of their mother.