Prince Philip has now spent a week in a London hospital .
The Duke of Edinburgh was said to have walked unaided into King Edward VII’s hospital last Tuesday evening.
Buckingham Palace said it was a precautionary measure after the 99-year-old felt unwell.
However his grandson, Prince William, has since stated he is doing "OK".
At a visit to a Norfolk vaccination centre on Monday, The Duke of Cambridge revealed doctors are "keeping an eye on him".
His eldest son, Prince Charles, made a 200-mile round-trip from his home in Highgrove, Gloucestershire, on Saturday afternoon.
He was the first family visitor for a man, who royal sources claim isn't a fan of "fuss".
There was some criticism of the visit given the current Covid-19 restrictions, although the hospital's website states visits are considered in "exceptional circumstances”.
Sources previously told the PA news agency that Philip was likely to remain in hospital into the coming week for "observation and rest".
There have been some touching gestures outside the hospital from well-wishers, including heart-shaped balloons tied to the railings.
