The Queen and prime minister have led tributes at the annual Remembrance Day service in London in honour of the servicemen and women who died for their country.
The two minute silence was followed by wreath laying
A shot fired at 1100 GMT marked the start of the two-minute silence to remember the nation's war dead, including more than 50 British soldiers who died in Iraq.
Royal Marine buglers sounded the Last Post before the Queen laid the first of a carpet of wreaths at the Cenotaph in Whitehall.
Three World War I veterans, all aged over 100, rode in an open top car to lead the 10,000 ex-servicemen and women and some 1,600 civilians in a march past the country's main war memorial.
Services were also held across the UK and by British soldiers in Iraq.
The Queen was followed by the Duke of Edinburgh, the Duke of York, the Princess
Royal, the Duke of Kent and Prince Michael of Kent in laying wreaths.
Tony Blair led senior politicians including Australian Prime Minister John Howard and Conservative Party leader Michael Howard in paying tribute to the war dead.
A government spokesman said: "The service at the Cenotaph is framed to ensure that no-one is forgotten.
"Tributes placed on the Cenotaph are dedicated to all who have suffered and died in war."
The ceremony first held in 1921 to remember those who gave their lives during World War I now includes all who have died in conflict in the service of their country.
This year friends and relatives of servicemen and women who died in
non-combat situations also laid a wreath of poppies.
Geoff Gray, whose 17-year-old son Geoff died at Deepcut Army barracks, in Aldershot, Surrey, was among those paying tribute.
His son was among four recruits to die at the barracks.
An inquest into Private Gray's death returned an open verdict after
the recruit was found with two gunshot wounds to his head while on guard duty in September 2001.
Mr Gray said: "We all felt extremely honoured and proud to be there.
"We remember Geoff every day but today was a little bit special."
Ahead of the two minute silence the Royal British Legion said it hoped three-quarters of the country would pause to mark the moment the guns fell silent at the end of World War I.
In Iraq, the lives of seven servicemen - six British and one American - killed in a collision between two Sea King helicopters in the Gulf were marked with a wreath at the accident site.
The Commander of the British Maritime Forces Rear Admiral David Snelson placed the wreath.
In a separate ceremony, about 500 troops paraded past the old war memorial in Basra, southern Iraq.
The names of all the British servicemen who died in Iraq were read out during the service.
Earlier on Sunday the Prince of Wales, on a visit to Oman, attended a Remembrance Day service and laid a wreath at the Ras Al Hamra Christian cemetery.
On Saturday night the Queen, accompanied by the Duke of Edinburgh and other members of the Royal Family, attended a Remembrance Festival at the Royal Albert Hall in London.
Tony Blair was also at the event, organised by the Royal British Legion.