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The Duke of Edinburgh has left hospital after being admitted two days ago as "a precautionary measure".

Prince Philip was treated at the private King Edward VII Hospital, in central London, for an infection arising from a pre-existing condition.

A Buckingham Palace spokeswoman had said on Wednesday that the 96-year-old was in good spirits.

The BBC understands his condition is "not a cause for serious concern".

The duke left from the rear of the private hospital just before 10:00 BST on Thursday, and was driven away.

He had been with the Queen at Trooping the Colour on Saturday and the opening day of Royal Ascot on Tuesday.

However, after being admitted to hospital on Tuesday evening, he missed Wednesday's State Opening of Parliament, where his place was taken by the Prince of Wales, and a second day at Ascot.

It is understood the duke was not admitted to hospital as an emergency but, on a doctor's advice, was driven from Windsor Castle.

BBC royal correspondent Peter Hunt said that, given the duke was treated for a pre-existing condition, it is safe to assume he has been suffering from the recurrence of the bladder infection he suffered twice in 2012.

Prince Philip has spent much of his life in good health, but he was treated for a blocked coronary artery in 2011 and the bladder infection the following year.