Prime Minister Andy Burnham said the annual event was a time to “reflect on the selflessness and courage it takes to commit your life to protecting others”.
He earlier announced that he wanted to tackle the problem of homelessness among ex-service personnel to “ensure that any veteran sleeping rough is offered appropriate accommodation before Christmas”.
Mark Atkinson, the director general of the Royal British Legion, said: “As we come together on Remembrance Sunday, we pay tribute to all those who have served and sacrificed, from generations past to those still serving today.”
Remembrance events took place across the country as thousands gathered to pay their respects to those who died in past conflicts.
First Minister of Scotland John Swinney placed a wreath at the Stone of Remembrance outside the City Chambers during an event in Edinburgh.
Veterans, military personnel and cadets also marched through the centres of British cities such as Manchester, Birmingham and Leeds.
A silent poppy drop was held as part of the Festival of Remembrance at Durham Cathedral while wreaths were laid at Canterbury Cathedral.
Separately, the Duke of Sussex was seen attending a Remembrance service in the market town of Brackley in Northamptonshire.