The boat that will lead the procession down the Thames for the Queen's Diamond Jubilee Pageant will be put on the water later.
The royal row barge 'Gloriana' is the only boat to be constructed from scratch for the event.
Boat-builders have been working on it in a secret location for the last 18 weeks.
Along with the Spirit of Chartwell, which will carry the Queen down the Thames, Gloriana will be one of the most prominent boats in the pageant.
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