The Queen wiped a single tear away as the nation fell silent to commemorate all those who have died at war.
She watched her eldest son lay the first wreath at the Cenotaph from the balcony of the Foreign and Commonwealth Office, while the Duchess of Cornwall and the Duchess of Cambridge stood beside her.
Prime Minister Johnson and Labour's Jeremy Corbyn also laid wreaths, along with the SNP's Nicola Sturgeon and the Liberal Democrat's Jo Swinson.
This year is the 100th anniversary of the first Remembrance Sunday in 1919.
The Duchess of Sussex watched the ceremony from a separate balcony alongside the Duchess of Wessex.
Crowds began to gather at the Cenotaph in London several hours before the ceremony began.
During the wreath laying ceremony, which came after a two minutes silence, Prince William and Prince Harry followed their father in laying wreaths at the monument.
Later, in Dover, an aircraft dropped 750,000 poppies over the White Cliffs.
An original Second World War Dakota has dropped 750,000 poppies over the White Cliffs of Dover. #RemembranceSunday
Follow scenes live from across the country here: https://t.co/OkBubBUuky pic.twitter.com/U279oFcmsCâ€” Sky News (@SkyNews)November 10, 2019
Two minutes silence was observed as Big Ben struck 11am, with its beginning and end marked by the firing of a gun by the King's Troop Royal Horse Artillery.
Buglers of the Royal Marines sounded the Last Post before wreaths were laid at the Cenotaph.
A military band played as the politicians, religious leaders and diplomats from the Commonwealth of former British colonies laid wreaths on the Portland stone monument inscribed with the words "the glorious dead."
For the first time, the Ambassador of Nepal placed a wreath in honour of the contribution Gurkha regiments have made to Britain's military campaigns for the past 200 years.
Foreign Secretary Dominic Raab and Home Secretary Priti Patel laid wreaths on behalf of the intelligence services.
It is also the first time the services have been honoured in this way, coinciding with the 100th anniversary of the Government Communications Headquarters (GCHQ) and the 110th anniversaries of the Security Service (MI5) and Secret Intelligence Service (MI6).
A host of military and foreign representatives also laid wreaths by the Cenotaph, while other Cabinet ministers and religious leaders were in attendance.
After the wreaths were laid, the Bishop of London, Dame Sarah Mullally, led a short service of remembrance which ended with trumpeters of the Royal Air Force sounding Rouse (Reveille) and the singing of the national anthem.
Following the ceremony, up to 10,000 veterans and servicemen and women marched past the Cenotaph to honour the fallen.
In a decade-long tradition, London black cabs were on hand on Sunday to provide free transport to participating veterans from the capital's main train stations to Whitehall as a mark of thanks for their service.