The Duke of Edinburgh has said he is "disappointed" after being taken to hospital.
Prince Philip had been at Windsor Castle when he was admitted as a "precautionary measure" for treatment of an infection arising from a pre-existing condition, Buckingham Palace have said.
He had been due to accompany the Queen to today's State Opening of Parliament but the Prince of Wales will now do so.
It's already in the record books for stretching architectural boundaries and today it was given royal approval.
Brighton's i360 seafront attraction, described as a vertical pier in the sky, was officially opened by the Duke of Edinburgh. And unlike the early days everything went without a hitch.
Andy Dickenson reports and speaks to architects David Marks and Julia Barfield.
The Queen and the Duke of Edinburgh had an eventful day in Sussex visiting a brewery, a fish factory and a camping site!
The official visit was watched by hundreds of people who lined the streets to give them a rousing welcome.
Andrea Thomas has been following the day's proceedings.
Her Majesty The Queen and Prince Philip are visiting four locations in Sussex today.
Among the places to play host to the royal couple are Harvey's Brewery - the oldest independent brewery in Sussex; and the new archive for the University of Sussex.
The Duke of Edinburgh has been admitted to the Aberdeen Royal Infirmary as a 'precautionary measure', according to Buckingham Palace. Just on Monday Prince Philip appeared well, while at Cowes Week on the Isle of Wight to see the sailing.
This latest admission to hospital comes two-and-a-half months after Prince Philip spent five nights in hospital with a bladder infection, following the Diamond Jubilee Pageant on the River Thames.