LONDON (AFP) - Queen Elizabeth II led Britain in paying tribute to its war dead as the country fell silent on Remembrance Sunday.

The 87-year-old monarch laid a wreath at the Cenotaph national war memorial, accompanied by senior members of the royal family and prime ministers past and present.

In bright autumn sunshine as leaves fell from the trees above, thousands in central London observed a two-minute silence at 11am local time, started by chimes from the Houses of Parliament and round from a 13-pounder World War I gun.

The sovereign's husband Prince Philip and their grandsons princes William and Harry were among the royals in military uniform laying wreaths, in a service led by Richard Chartres, the Bishop of London.

It is the last such ceremony before next year's centenary of the start of World War I.

Conservative Prime Minister David Cameron, Liberal Democrat Deputy Prime Minister Nick Clegg and Labour opposition leader Ed Miliband laid wreaths, followed by the high commissioners of Commonwealth countries and armed forces chiefs.

Former prime ministers Gordon Brown, Tony Blair and John Major, this year without 1980s premier Margaret Thatcher who died in April, also paid their respects, as did leaders of 14 different religious denominations.

The ceremony was watched from the Foreign Office balcony by royal spouses including William's wife Catherine, the Duchess of Cambridge.

More than 10,000 veterans and civilians marched past the Cenotaph to pay their respects to departed comrades, to applause from members of the public.

Mr Andrew Jackson, 76, who served with the army in Suez in 1956, said: "It amazes me to see the number of people here - and especially to see so many youngsters. I think Remembrance Sunday has become more and more popular, and that people are becoming more aware."

British troops serving in Afghanistan were joined by Queen Elizabeth's second son Prince Andrew - a Falklands War veteran - who laid a wreath at their Camp Bastion base in southern Helmand Province.

Some 446 British troops have died serving in Afghanistan since operations began in October 2001, most recently Warrant Officer Class 2 Ian Fisher who was killed in a vehicle-borne suicide attack on Tuesday.

In the run-up to Remembrance Sunday, many Britons wear a paper red poppy - symbolising the poppies which grew on French and Belgian battlefields during World War I - in their lapels.

The proceeds from poppy sales go to veterans' organisation the Royal British Legion.