The nation will celebrate the Diamond Jubilee on Tuesday with a thanksgiving service, but the Duke of Edinburgh will be missing from the Queen's side.
Prince Philip is being treated in hospital for a bladder infection and will not be part of the events planned to mark the Queen's 60-year milestone on Tuesday.
Philip, 90, was taken to the King Edward VII Hospital in London from Windsor Castle yesterday as a precautionary measure.
He will remain in hospital under observation for a few days, a Buckingham Palace spokeswoman said.
Three police officers stood guard at the main entrance to the hospital this morning while other exits were also guarded and a police van was parked to the side.
The Archbishop of Canterbury, Dr Rowan Williams, is to give a sermon at the St Paul's Cathedral thanksgiving service and is expected to pay tribute to the Queen.
Gathered will be leading national figures and members of the Royal Family including Charles, the Duchess of Cornwall, the Duke and Duchess of Cambridge and Prince Harry. Meanwhile, Prime Minister David Cameron will lead the large representation from the coalition Government and other figures will include governor generals, diplomats and foreign leaders.
The Queen dazzled in a gold gown at the Diamond Jubilee concert last night
After the service the Queen will attend a reception at Mansion House while other senior royals including Charles and Camilla will attend a similar event at the Guildhall. At both events will be members of the thanksgiving congregation. The Queen and her family will then attend a City of London Livery companies lunch at Westminster Hall.
The highlight of the day will be a glittering carriage procession through the streets of Whitehall before the Queen and her family gather on Buckingham Palace's balcony to watch a flypast of Second World War aircraft and the Red Arrows.
The Prince of Wales paid a heartfelt tribute to his mother on Monday night, following the Diamond Jubilee concert staged near Buckingham Palace.
Stood on stage with the Queen a few feet away, Charles told hundreds of thousands who had gathered to watch the star-studded event that they were "celebrating the life and service of a very special person". But he added there was a disappointing element to the night. "The only sad thing about this evening is that my father cannot be her with us because unfortunately he's taken unwell," he said.
The Prince went on to say: "I was three when my grandfather George VI died and suddenly, unexpectedly you and my father's lives were irrevocably changed when you were only 26. So as a nation this is our opportunity to thank you and my father for always being there for us. For inspiring us with your selfless duty and service and for making us proud to be British."
Prince Charles got the 100,000-strong crowd laughing, as he called the Queen "Your Majesty... Mummy."
Referring to his father he lifted the celebratory mood, saying: "If we shout loud enough he might just be able to hear us in hospital." Which the crowd duly did.
He finally paid tribute to his parents' length of service, thanking the Queen "for inspiring us with your selfless duty and service and for making us proud to be British."
Celebrities attending the concert included Brian May, who famously played the national anthem on the palace's roof during the 2002 Golden Jubilee concert, television presenters Floella Benjamin and Kirstie Allsopp, and ex-Bond Girl Barbara Bach who is married to former Beatle Ringo Starr.
Take a look at some of the star spectators below
The royals stood for the final act, Sir Paul McCartney, who ran through a string of Beatles songs including Magical Mystery Tour, All My Loving and Let It Be.
After Charles' speech there was a huge fireworks display fired from the roof of the palace.