Spectators are eagerly awaiting the start of the Diamond Jubilee's most dramatic spectacle - the 1,000- strong flotilla in honour of the Queen.
Despite cold and wet conditions the capital filled steadily as the countdown has begun to the water-borne extravaganza that will carry the Queen through London at the heart of the procession.
Organisers have remained upbeat about the day ahead, as have members of the public who have been flocking to the Thames armed with umbrellas and raincoats.
Boats line up on the Thames to take part in the flotilla
The Prince of Wales is patron of the pageant that will be launched later this afternoon following two years of trials, rehearsals and planning.
Charles and his wife Camilla ventured out into the rain earlier to join a Big Jubilee Lunch street party in London's Piccadilly.
The prince, wearing his trademark double breasted suit, and Camilla, dressed in a raincoat, stopped to chat to revellers in the street and even sat down with them.
London Mayor Boris Johnson was upbeat from Putney Pier, declaring the rain had passed as he geed-up the crowds around him.
"I want you to know the rain has stopped, hasn't it?" the politician said, turning to a crowd behind him while being interviewed by BBC News.
He added: "It's going to be a fantastic day, I've no doubt about that at all.
"We're are looking forward very much here in Putney to the kick-off, which I think is in a couple of hours time, but already the crowds are enormous here."
Spectators are enjoying some respite from the rain which has stopped in most places but forecasters have predicted sunshine and showers during the afternoon.
During the week, hundreds of ships travelled up the Thames and have now mustered south of Battersea Bridge as crowds gather along the banks of the river.
Decorations for the Royal Barge were completed in the last few days with ornate replica carvings fitted to the vessel and huge floral decorations.
It will carry the Queen and Duke of Edinburgh, Charles and Camilla, the Duke and Duchess of Cambridge and Prince Harry at the heart of the flotilla.
Pageant Master Adrian Evans said: "Key highlights for me are the royal barge and how people will see that for the first time and certainly how the Queen and the Royal Family see it."
Evans was not concerned about the rain that had fallen on much of the seven-mile long course of the flotilla.
He said: "There is some rain around, but it has not dampened any spirits.
"We in Britain are experts at not letting the weather spoil our fun. The London Philharmonic Orchestra will be playing Singing In The Rain as they travel down the river, and the crowd can sing along with them.
"We are all set to have one of the most spectacular pieces of river theatre that London, and the world, has ever seen. Excitement is building, and everything is ready."
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