Britons on Saturday began four days of festivities for Queen Elizabeth II's diamond jubilee, turning out in droves for events around the country in a surge of enthusiasm for the monarchy.
Gun salutes across Britain were due to launch celebrations at 1200 GMT, marking the exact anniversary of the queen's coronation, while the sovereign herself was to indulge in her love of horse racing at the Epsom Derby.
Tens of thousands of people were awaiting the queen at the racecourse, while thousands more paraded through the Scottish city of Perth, held community parties and even travelled to watch military bands rehearse in London ahead of the main celebrations.
"It's not every morning you wake up on a day that will be written about in the history books," declared the Sun, Britain's best-selling newspaper.
"Make the most of this once-in-a-lifetime occasion. It may be centuries before another comes along."
Cloudy weather and forecasts of rain appeared unlikely to deter the public from partying amid the highest support for the royals in decades. A recent poll showed about 80 percent of Britons want the country to stay a monarchy.
People were already camping in tents beside the Thames river ahead of a pageant of about 1,000 boats that will sail through London on Sunday with the 86-year-old queen in a royal barge decked with 10,000 flowers.
Britons have planned more than 9,500 street parties for Sunday, and on Monday, some 4,000 beacons will be lit across the Commonwealth following a huge picnic and star-studded concert at Buckingham Palace.
Tuesday -- like Monday a public holiday -- is devoted to ceremonial events including a thanksgiving service and carriage procession.
Crowds of racegoers, some in top hats and tailcoats, were arriving at Epsom just outside London on Saturday in anticipation of the monarch's appearance at a racecourse whose tents were covered with Union Jack flags and bunting.
The queen, an avid horse-racing fan who still rides despite her age, was expected to be driven down the course in an open-topped vehicle with husband Prince Philip, 90, before a flag-waving crowd of over 150,000.
The Red Arrows aerobatic team will give a display of daredevil flying, and mezzo-soprano Katherine Jenkins will perform the national anthem ahead of the Epsom Derby, Britain's richest horse race, which dates back to 1780.
The monarch will present the 110-year-old Coronation Cup -- renamed the Diamond Jubilee Coronation Cup -- to the winner of a race run on the same course as the Derby.
Some 72 horses and six World War I-era 13-pounder gun carriages were meanwhile headed for parade grounds in central London for a 41-gun salute to be echoed around the country.
Thousands of people including 1,000 pipers and drummers were parading through the Scottish city of Perth despite an ongoing campaign north of the border for independence from the United Kingdom.
In Northern Ireland, even republican party Sinn Fein has supported celebrations and offered a gift to the queen for the occasion.
Political leaders lined up ahead of the revels to praise the queen, who in 60 years on the throne has won a reputation for shrewdness and devotion to duty, an unflappable demeanour and a seemingly infinite collection of hats.
Prime Minister David Cameron said in a video tribute, "I think it's hugely important. The queen has given incredible service -- 60 years on the throne, a lifetime of service -- she's never put a foot wrong.
"She's hugely popular and respected, and it's an opportunity for people to give thanks and say thank you."
Festivities are set to be more muted across the Commonwealth, mostly made up of former British colonies, but British soldiers were pictured in Afghanistan serving celebratory tea from a gold-coloured teapot.
In the Telegraph newspaper, Michael Lockett, chief executive of the Thames Diamond Jubilee Foundation, said bad weather should not stop the nation taking the chance to "be part of history."
"In these austere times, we need cheering up more than ever," he added, while royal watchers recalled it had poured with rain on the day of the queen's coronation.
The queen acceded to the throne on February 6, 1952, upon the death of her father King George VI while she was away in Kenya, and was crowned the following year on June 2.