Britain's Queen Elizabeth joined an armada of 1,000 boats down London's River Thames to the pealing of bells on Sunday in a spectacular highlight of four days of nationwide celebrations to mark her 60th year on the throne.

Hundreds of thousands of cheering people waving "Union Jack" flags and dressed in red, white and blue braved the wind and rain to pack the 7-mile (11 km) route for one of the largest flotillas ever seen on the river.

The queen, wearing a silver and white dress with a matching coat, smiled broadly and waved to large crowds before boarding the gilded royal barge, "The Spirit of Chartwell", alongside her 90-year-old husband Prince Philip.

Other members of the royal family on the barge included heir-to-the-throne Prince Charles, his eldest son Prince William and new wife Kate, a global fashion trendsetter who wore a vivid red Alexander McQueen dress and matching hat.

Up and down the country, millions of people were due to attend diamond jubilee street parties over the long holiday weekend in honour of the 86-year-old, the only British monarch after Queen Victoria to have sat on the throne for 60 years.

Leisure cruisers, rowing boats, yachts and canoes made up the colourful Thames armada that also featured vessels from the 1940 evacuation of British and Allied troops from Dunkirk in northern France - a famous rescue performed by crafts of all shapes and sizes and a celebrated piece of British history.     

A typically inclement British summer's day failed to dampen enthusiasm, with boisterous crowds massed along the banks of the Thames, watching giant TV screens showing black-and-white images of the queen from her childhood.

"We're English, we know what the weather is like. We really don't care if we get wet you know - it's the jubilee, it's the queen, so it's nice to come up and celebrate it," said Jackie, a 39-year-old sales consultant who travelled across southern England to watch the event.

Organisers say Sunday's river pageant is the largest of its kind in 350 years since a similar spectacle was held for King Charles II and his consort Catherine of Braganza in 1662.

Across England, Scotland, Wales and Northern Ireland, street parties were being held to mark the occasion. Prince Charles and his wife Camilla dropped into one in central London before the pageant, joining in a rousing rendition of the national anthem.

While the queen and the royal party braved the elements under a golden canopy on a barge in the middle of the Thames, the wet conditions proved too much for Prime Minister David Cameron, who moved his Downing Street party indoors.

That said, the government hoped the festivities would mark the start of a summer of revelry capped off by the Olympic Games in London, raising the public's spirits and their poll ratings.

 "What is great is that we have the jubilee and then the Olympics. We should show how great we are in Britain," said Joanne Richmond, 61, from central England, who was in London for the queen's coronation as a two-year-old.  - Reuters