Services will take place across the country later to mark Remembrance Sunday.
A two-minute silence will be held at precisely 11:00 GMT to honour all those who have died in conflict.
The Queen will lead the commemorations at the Cenotaph in London. Prime Minister Theresa May and other party leaders will also attend.
On Saturday evening the Queen attended the 93rd Festival of Remembrance at the Royal Albert Hall.
At the Cenotaph, the Queen will lay the first wreath, followed by the Duke of Edinburgh and the Prince of Wales.
More than 700 soldiers, sailors and members of the RAF will line Whitehall.
Detachments from units such as the Royal Marines, Household Cavalry and Royal Gurkha Rifles will flank the stone memorial.
Elsewhere, more than 40,000 knitted poppies have been placed on a Remembrance Day parade route in Thirsk, North Yorkshire.
The organisers said volunteers had sent in knitted and crocheted flowers from all over the world.
In Croydon, where seven people were killed and 50 injured after a tram derailed earlier this week, special prayers will be said for those affected.
Images of poppies will projected onto the Queen Elizabeth tower at Parliament on Sunday afternoon.
- Remembrance Sunday always falls on the second Sunday of November
- The artificial poppy was adopted and popularised in 1921 by Douglas Haig and the Royal British Legion
- In 1947 it was agreed that both World War One and World War Two would be remembered on just one national day, Remembrance Sunday
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The prime minister has said the day is not only about honouring the dead but also for paying tribute to those members of the armed forces currently on active service combating so-called Islamic State.
Mrs May said: “The way of life we enjoy today depends upon the service offered by members of the armed forces and their families.
“Across generations, and in every corner of the UK, today we remember those who gave so much for our values, our democracy, and our nation.”
Scotland’s First Minister Nicola Sturgeon will attend the annual wreath laying and Remembrance Sunday service at St Giles’ Cathedral in Edinburgh.
The Irish Prime Minister and Northern Ireland’s First Minister will attend a Remembrance Sunday ceremony in Enniskillen, Fermanagh.
And there will be a National Service of Remembrance for Wales at Cathays Park in Cardiff.
The Imperial War Museums are releasing letters, photographs and memoirs donated by families of soldiers killed in the Battle of the Somme in 1916, the bloodiest clash in World War One.
The documents originally formed part of the museum’s Bond of Sacrifice collection dating from its formation in 1917.
Contributions included a photograph of two brothers who it is said were within 50 metres of each other when one was wounded and the other rushed to his aid and was shot.
They died in each other’s arms, and their mother received one telegram in the morning informing her of one son’s death, and later the same day, another telegram telling her the other son had died.
The documents will now be part of the Lives of the First World War digital memorial.
At the Royal Albert Hall on Saturday evening, the Queen and other members of the Royal Family stood to applaud a procession of bereaved families.
It came after the audience heard the story of Cyrus Thatcher, who was killed in 2009 aged 19 while fighting as a rifleman in Afghanistan.
The Queen and the rest of the royal box joined the standing ovation as his parents, Helena Tym and Robin Thatcher, led a procession of bereaved families through the hall.
This year the event marked the centenaries of the Battle of the Somme and the Battle of Jutland, the 25th anniversary of the Gulf War and the 80th anniversary of the first flight of the Supermarine Spitfire.
Thousands of poppies fluttered to the ground from the hall’s domed roof as the room observed a two-minute silence.