The Queen at the Cenotaph in central London
The UK fell silent in tribute to service personnel who have died during conflicts, as part of the annual Remembrance Sunday service.
A two-minute silence was observed, before the Queen laid the first wreath at the Cenotaph in central London.
The monarch joined more than 10,000 veterans plus political, Commonwealth and religious leaders at the ceremony.
Services have taken place at memorials across the UK, in Commonwealth countries and at military bases abroad.
The Last Post was sounded following the silence, and the monarch then laid her wreath at the foot of the monument, the focal point of the UK's Remembrance Sunday events.
The marchers will shortly set off down Whitehall.
Prince Harry laid a wreath on behalf of his father, who is in India
The leaders of the UK's political parties have laid wreaths
Veterans have gathered at the Cenotaph
The Duchess of Cambridge was accompanied on the Foreign Office balcony by the Countess of Wessex and
Vice Admiral Tim Laurence
A ceremony was held at Camp Bastion in Helmand Province earlier, with tributes lead by Prince Andrew
Representatives of a World War Two unit known as "Churchill's Secret Army" are taking part for the first time.
In Scotland, First Minister Alex Salmond and Scottish Secretary Alistair Carmichael are laying wreaths at St Giles Cathedral in Edinburgh.
In Wales, a national event is taking place at Cardiff's Welsh National War Memorial, while in Northern Ireland events include services in Belfast and Enniskillen.
At the Cenotaph, the Queen laid the first floral tribute, followed by the Duke of Edinburgh, the Duke of Cambridge and Prince Harry.
Prime Minister David Cameron and other party leaders also left floral tributes at the monument.
Prince Charles laid a wreath at the Kirkee
Commonwealth Cemetery in India
Marching for the first time are 41 members of the British Resistance Movement - known as Churchill's Secret Army or the Coleshill Auxiliaries - volunteer fighters charged with going underground to continue the fight in the event of a German invasion of Britain in World War Two.
At Camp Bastion in Helmand Province, a service was held to remember the 446 servicemen killed in the 11 years of conflict in Afghanistan.
After the Last Post sounded, wreaths were laid by the Duke of York and Defence Secretary Philip Hammond.
'Mates left behind'
The Prince of Wales and the Duchess of Cornwall also marked the event during their official tour of India, joining the congregation of a Mumbai church for their annual remembrance service.
The couple met some of India's last surviving World War Two veterans - Brig Furdoon Mehta, 91, the first Indian Army aviator, and Madhukar Dongre, 92, the last surviving recipient of the Burma Star living in India.
George Batt, national secretary of the Normandy Veterans Association who fought on D-Day, said Remembrance Sunday was a time for reflection.
"We'll be remembering all our mates that we left behind out there who paid the supreme sacrifice. And today, really, brings home the sadness of it all. And I must say, the stupidity of war," he said.
Kerry Ashworth, whose son James was killed in Afghanistan last year and was posthumously awarded the Victoria Cross for bravery, said it was a special day for everyone.
"The job that they do is so hard and so tough and when somebody loses their life, it's just one little thing that you can do just to remember them for a few minutes," she said.