A seven-mile flotilla of 1,000 ships will sail down the River Thames in one of the biggest and most spectacular events ever seen in London to mark Queen Elizabeth's 60 years on the throne, organisers said on Wednesday.

The 10 million pound pageant will include a royal barge and feature some 20,000 participants, historic boats, working vessels, small kayaks, musicians and an orchestra, as well as a unique floating bell tower.

Organisers predict millions will watch along the 25-mile stretch of the river where the flotilla will pass, with hundreds of millions expected to tune in on TV across the world to see the most dramatic display of British pomp and ceremony witnessed on the river since the 17th century.

The idea of the flotilla has inspired and captured the imagination of everyone, literally worldwide, said Michael Lockett, chief executive of the Thames Diamond Jubilee Festival.

He called it an event of monumental proportions, the scale of which has never previously been undertaken, certainly in London.

It is 350 years since there was a gathering of similar scale on the Thames, he added.

The pageant will take place on Sunday June 3 during four days of celebrations to herald the queen's jubilee, travelling under 14 bridges along the Thames and taking some 90 minutes to pass any point along the way.

The flotilla will involve 10 sections, each one led by a music barge. At its head will be the 88-foot (27-metre) royal rowbarge, powered by 18 oarsmen, while the queen and her husband Prince Philip will be aboard a specially adapted cruiser, the Spirit of Chartwell royal barge.

Other vessels include Motor Torpedo Boat 102 on which Prime Minister Winston Churchill and U.S. President Dwight Eisenhower inspected warships before the 1944 D-Day invasion of France and the yacht Eilean which appeared in the video for pop band Duran Duran's hit single Rio.

Pageant Master Adrian Evans said it would be the greatest collection of historic vessels ever to be gathered in London.

In all, the event will encompass a 30-mile stretch of river from Hammersmith in west London to Greenwich in the east, with a free festival for visitors in Battersea Park, which adjoins the river.

London Mayor Boris Johnson said the event had excited some people more than the Olympic Games which comes to the city the following month.

(Editing by Paul Casciato)