The queen will lead the flotilla which is expected to be 12 km long and made up of rowing boats, sailing ships, steamers, wooden launchers and large motorized craft from across Britain.

Up to a million people are expected to line the banks of the river to watch the spectacle to be held on June 3, 2012, which will also feature daytime fireworks and a mechanical flame-spitting dragon.

“I cannot conceive of a more fitting celebration of Her Majesty’s 60 years on the throne than a majestic flotilla of vessels, large and small, winding their way along the iconic River Thames,” London Mayor Boris Johnson said.

“This magnificent pageant will not only provide a terrific focal point for Diamond Jubilee commemorations, but will demonstrate to the world London’s pride in its heritage and traditions.” Letters have been sent to High Commissioners of every Commonwealth country inviting them to send a vessel while individuals and associations can also apply to take part.