|The Duke of Edinburgh was admitted to a cardiac hospital after suffering from chest pain [Reuters]
UK's Prince Philip has been recovering and in "good spirits" from heart surgery and is bound to miss much of the royals' Christmas celebrations at their rural Sandringham estate.
"Prince Philip was in good spirits, but he is eager to leave," a spokeswoman for Buckingham Palace said on Sunday. "He will remain in hospital under observation for a short period."
Prince Philip, also known as the Duke of Edinburgh, had a coronary stent put in late on Friday to fix a blocked artery, though the palace has refused to say if he had a heart attack.
"The Duke of Edinburgh was found to have a blocked coronary artery which caused his chest pains," the palace said.
On Saturday, Philip received visits from Queen Elizabeth II and his four children at Papworth Hospital in Cambridge, where he was admitted after experiencing chest pains at the Sandringham estate in Norfolk.
Heir-to-the-throne Prince Charles and siblings Prince Edward, Prince Andrew and Princess Anne also visited the hospital to see their recuperating father.
Philip, 90, who married Elizabeth in 1947, was a pivotal figure in the House of Windsor, and has a reputation as a fiercely loyal consort who prefers outdoor pursuits to introspection.
The minor operation involves using a catheter to insert a small tube into the artery to clear any blockages.
Coronary stenting is standard procedure both to fend off a heart attack or save a patient already in the midst of one, said Dr Allan Schwartz, chief of cardiology at New York-Presbyterian, Columbia University Medical Centre.
"Coronary stenting is standard procedure both to fend off a heart attack or save a patient already in the midst of one"
-Dr Allan Schwartz,
Columbia University Medical Centre
"It is a big spectrum, there's no way of knowing what applies to him,'' Schwartz said, adding "you're taken to the hospital with chest pain is like saying you're taken to the hospital with a gunshot wound. It could be a grazing shot that's not significant or it could be something that's serious".
In addition to well-wishers gathered outside Papworth Hospital, British Prime Minister David Cameron also offered his support to Philip.
"The prime minister has been kept informed of the situation and wishes the Duke of Edinburgh a very speedy recovery,'' Cameron's office said.
Born on the Greek island of Corfu in 1921, Philip served in Britain's Royal Navy before marrying Elizabeth. They have four children, including the heir to the throne, Charles.