A file photo shows Britain's Prince Philip waving to members of the media as he leaves the King Edward VII Hospital after treatment in London June 9, 2012.  [Photo/Agencies]

LONDON - A smiling Prince Philip, the 92-year-old husband of Britain's Queen Elizabeth, left hospital after 11 days on Monday, slightly earlier than expected, following an operation on his abdomen.

Looking sprightly and in good spirits, the prince walked unaided out of the London Clinic, shaking hands with the staff and waving to onlookers outside, before getting into his car to be driven to Windsor Castle, west of London.

Philip, also known as the Duke of Edinburgh, had been taken to hospital on June 6 for the planned operation, the fourth time he had been hospitalised in the last 18 months.  

"The Duke has expressed his thanks and appreciation to the medical staff at the London clinic and to members of the public for their good wishes," a Buckingham Palace spokeswoman said.

The prince, who was visited by his 87-year-old wife of more than 65 years and other senior members of the royal family during his stay, had been expected to remain at the clini for two weeks after undergoing what the palace described as an "an exploratory operation following abdominal investigations".

The palace said the results of the operation would be analysed, while Philip would take a period of convalescence of approximately two months. He is expected to resume engagements in the autumn.

The longest-serving consort of any British monarch and the oldest living great-great-grandchild of Queen Victoria, Philip has had a number of health issues in recent years.

He was hospitalised for a bladder infection during the queen's Diamond Jubilee celebrations last year, and spent Christmas 2011 in hospital where he underwent an operation to clear a blocked heart artery after suffering chest pains.