Prince Philip is expected to spend a third night in a London hospital for “observation and rest” after being admitted earlier this week while feeling unwell.

The Duke of Edinburgh was described as being in “good spirits” after he walked unaided into King Edward VII’s hospital in central London on Tuesday night on the advice of his doctor.

Buckingham Palace has said admitting the 99-year-old husband of Queen Elizabeth was a “precautionary measure”.

There were no reports of visitors arriving at the private hospital on Thursday but the duke is known for his no-fuss attitude.

Royal author Penny Junor joked that medics probably would not want the duke on their shift due to his aversion to people “fussing over him”.

While he has been in hospital, the royal family have been working as usual. The Queen has carried out her normal duties of state this week and on Wednesday the Prince of Wales and Duchess of Cornwall visited a Birmingham hospital to learn about vaccine trials.

“He can be quite blunt and I think if he felt people were fussing over him he could be quite outspoken about that,” Junor told BBC Breakfast.

“This is a man who doesn’t want any fuss made of his 100th birthday, so the fact he’s in hospital and getting some fuss made of him will really irritate him.”

Philip’s hospital admission is front page news and outside King Edward VII’s photographers, the media has gathered to cover any developments.

The duke, who turns 100 on June 10, has so far spent two nights in hospital for an undisclosed reason although it is not coronavirus-related.

It is understood a doctor was called after Philip felt unwell for a short period and he was taken to hospital by car, where he walked in unaided as a non-emergency admission.

-AAP