Prince Philip is to spend a third night in hospital where he is receiving treatment for a bladder infection.
He has had no visitors on Friday after doctors advised him to rest.
The Duke of Edinburgh. 91, was taken to Aberdeen Royal Infirmary on Wednesday from Balmoral.
It is his third hospital stay in nine months.
Prince Philip was admitted to hospital for five nights during the Queen's Diamond Jubilee in June. He also spent four days in hospital at Christmas, following an operation to clear a blocked heart artery.