The Duke of Edinburgh has an infection and is not expected to leave hospital for several days, Buckingham Palace has announced.
He is "comfortable and responding to treatment", the Palace said.
What is the Duke of Edinburgh’s current condition?
Prince Philip has spent eight nights in hospital so far. A Buckingham Palace source said on Friday (19 Feb) that it was likely the Duke of Edinburgh would remain in hospital this week.
His stay is unrelated to coronavirus. Both he and the Queen received a first dose of a Covid-19 vaccine in early January.
Speaking to reporters on a visit to a coronavirus vaccination centre in Norfolk on Monday (22 Feb), when asked about his grandfather’s condition Prince William said: “Yes, he’s okay, they’re keeping an eye on him.”
The Duke of Edinburgh was admitted to King Edward VII Hospital on 16 February on the advice of his doctor, in what Buckingham Palace described as a "precautionary" move.
On Tuesday (23 Feb), the Duke's youngest son Prince Edward, told Sky News he was feeling "a lot better" and "looking forward" to getting out of hospital.
A Palace source previously said that the Duke of Edinburgh, who is turning 100 in June, had arrived into the London hospital unaided.
His son, Prince Charles, visited on the afternoon of 20 February, and spent about 30 minutes at the hospital.
Throughout the lockdown in England, the Queen and Prince Phillip had been staying at Windsor Castle. Prince Philip, who retired from public duties in 2017, rarely appears in public. His most recent public event was a military ceremony at Buckingham Palace in July.