The King led a Remembrance Day service at the Cenotaph this morning, surrounded by thousands of veterans and members of the public.
He joined the country in commemorating the end of the First World War and other conflicts involving British and Commonwealth forces.
Almost 10,000 veterans and 800 armed forces personnel from all three services took part in a march-past, with a two-minute silence held across the UK at 11am.
Wreaths were laid by members of the Royal Family, senior politicians and dignitaries at the Cenotaph. They were joined by thousands of members of the public lining Whitehall to watch the service.
Nuclear test veterans, who for the first time wore medals acknowledging their contribution, were among those attending.
After 70 years of waiting for recognition, those exposed to the effects of nuclear bombs during the UK's testing programme were given a medal - depicting an atom surrounded by olive branches - for the Remembrance Sunday service.
More than 300 different armed forces and civilian organisations were represented, as well as some 300 veterans not affiliated with an association who were invited to join for the first time.
They also marked 70 years since the end of fighting in the Korean War and 20 years since the start of the UK's military operations in Iraq.
Prime Minister Rishi Sunak said ahead of the service: "The courage and commitment shown by our servicemen and women, both today and throughout the generations that came before them, is humbling and I know many across the country will be honouring their memory today in quiet reflection."
Mr Sunak said recent events served as a "stark reminder that we cannot take the hard-earned peace we live in for granted".
Memorial marred by protests
This weekend's services have been marred by protests, with 126 arrests made - including at least 92 right-wing counter-protesters - according to the Metropolitan Police.
The force has been under pressure to prevent disruption at events after tensions surrounding Saturday's pro-Palestine march and counter-protests.
The number of officers on duty in the capital was double the usual amount, with about 1,375 officers today, and the Cenotaph had a dedicated 24-hour police presence until the conclusion of Remembrance events.
Around 150 pro-Palestinian protesters were intercepted on Saturday night after breaking away from the main group following a 300,000-strong march through central London. It is understood that not all of these people were arrested.
Police are "actively looking" for individuals seen carrying antisemitic placards at the demonstration, which they said remained "largely peaceful".
The marches have become a feature of weekends in the capital since Israel struck back against Hamas after the group, a proscribed terrorist organisation in the UK, killed 1,400 Israelis and took hundreds hostage.
Braverman saga rumbles on
The prime minister remains under pressure to sack Home Secretary Suella Braverman after she branded the pro-Palestine protests "hate marches" in an article in The Times.
Labour leader Sir Keir Starmer accused her of "sowing the seeds of hatred" and Mayor of London Sadiq Khan also called for her to be relieved of her post.
Her comments have also caused a rift in the Conservative party, with numerous Tories privately calling for her to be given the boot, while former Tory MP Dominic Grieve has publicly called for her to be removed and even barred from laying a wreath at the Remembrance service.