The Duke of Edinburgh was admitted to hospital on Tuesday as a precautionary measure for an infection arising from a pre-existing condition.
A file photo of Prince Philip, who was with the Queen at Royal Ascot on Tuesday.
Photo: AFP
Buckingham Palace said Prince Philip was being treated at the King Edward VII Hospital in London and was up and about and in good spirits .
The duke, 96, said in May that he would retire from royal duties this autumn - a move supported by the Queen.
She is still carrying out her official engagements and on Wednesday delivered the Queen s Speech to Parliament before heading to the racing at Ascot.