The mourners at Westminster Abbey will be joined by two of the Queen’s great-grandchildren, Prince George and Princess Charlotte, who will attend the state funeral with their parents, the Prince and Princess of Wales.
The nine-year-old future king and his seven-year-old sister will gather with 2,000 people in the abbey to remember their late great-grandmother as millions more watch the televised service across the globe.
The young royals will walk with the royal family in procession behind the Queen’s coffin as it is carried by the military bearer party.
Their grandfather, the King with the Queen Consort will process immediately behind the coffin, followed by the Princess Royal and Vice Admiral Sir Tim Laurence, then the Duke of York, followed by the Earl and Countess of Wessex, and then the Prince and Princess of Wales.
George and Charlotte, who called the Queen “Gan Gan”, will be together, behind their parents, walking side-by-side in formation, followed by their uncle and aunt the Duke and Duchess of Sussex, and other members of the family.
The second and third in line to the throne are also expected to be at the committal service in St George’s Chapel, Windsor Castle afterwards.
Their four-year-old brother Prince Louis will not be there. His playful antics on the balcony for the Platinum Jubilee delighted royal fans but he is likely considered too young to attend.
At the end of the service, following The Last Post, two minutes’ silence, the Reveille, and the national anthem, the Queen’s Piper, Warrant Officer Class 1 (Pipe Major) Paul Burns, will play the traditional lament Sleep, Dearie, Sleep.
Before the service, the tenor bell will be tolled every minute for 96 minutes, reflecting the years of the Queen’s life.
The Dean of Westminster, the Very Reverend Dr David Hoyle, will speak of the Queen’s “unswerving commitment to a high calling over so many years” as Queen and Head of the Commonwealth.
One of the hymns – The Lord’s My Shepherd, I’ll Not Want – was sung at the Queen’s wedding, when she married the Duke of Edinburgh in the same abbey, as a 21-year-old bride in 1947.
The others hymns are: The Day Thou Gavest, Lord, Is Ended; and Love Divine, All Loves Excelling.
The latter has often featured at royal weddings including William and Kate’s, Charles and Camilla’s wedding blessing, and Princess Eugenie’s.
Prime Minister Liz Truss and Baroness Scotland, the Secretary-General of the Commonwealth, will both give bible readings during the service.
Hundreds of extra trains have been laid on to bring in mourners to share the occasion, while some roads will be closed to help keep the capital’s transport system flowing.
Around 250 extra rail services will run – including some overnight trains – and National Highways has suspended planned motorway closures across England.
There are fears the transport network will be overwhelmed on Monday afternoon if too many people visiting the capital travel home immediately after the funeral procession leaves Westminster shortly after noon.
TfL boss Andy Byford told the PA news agency: “We’re ready for probably one of the busiest days Transport for London has ever faced.
“It’s hard to say exactly how many additional people (will travel), but we’re preparing for potentially a million people just within the footprint of the royal palaces and Hyde Park.”
Mr Byford said TfL is “leaving nothing to chance” to ensure visitors can “get around the city”.
Network Rail chairman Sir Peter Hendy warned trains will be “extremely busy”.
He said: “This is the biggest public transport operation since the London 2012 Olympic and Paralympic Games, and we’re working closely with all train operators to run extra trains through the day and into the night.
“To help us provide the best possible experience and avoid lengthy queues at stations we’re asking people not to rush home after the funeral and the processions, but to take their time and experience London on this memorable day.”
Stationary trains are being used as waiting areas in the early hours of the morning for people waiting to catch a train home. Priority will be given to elderly and vulnerable mourners.
Three Tube stations – Westminster, St James’s Park and Hyde Park Corner – will be closed for most of Monday morning to avoid overcrowding.
More than 100 Heathrow Airport flights will be cancelled to prevent aircraft noise disturbing proceedings at Westminster Abbey and Windsor Castle.
The west London airport announced 15% of its 1,200 flights due to take off or land on Monday will be disrupted.
British Airways – the most-affected airline – cancelled 100 short-haul flights due to the restrictions.