LONDON : Queen Elizabeth II’s husband Prince Philip is “comfortable” as he recovers from exploratory abdominal surgery in aLondonhospital,BuckinghamPalacesaid on Saturday. The 91-year-old had surgery at the private London Clinic inHarley Streeton Friday following tests earlier in the week, and was said by the palace to be “progressing satisfactorily”. The results are now being analysed, and the duke ofEdinburghis likely to stay in hospital for up to two weeks. The queen, 87, is spending the weekend atWindsorCastle, and is being kept fully informed of her husband’s progress.

The monarch was asked about the duke’s health when she toured the BBC’s refurbished headquarters inLondonat a pre-planned engagement on Friday morning, but typically gave little away.

John Humphrys, one of the BBC’s top presenters, asked how Prince Philip was. She replied: “I don’t know.”

The broadcaster said he had looked well at aBuckinghamPalacegarden party just before entering hospital on Thursday evening, and the monarch stated: “That’s because he’s not ill.”

The queen and Philip have been married since 1947, and she once described him as “my strength and stay all these years”.

Palace aides insist Philip is generally in good health and noted he walked into the hospital unaided, but his fourth admission in two years has sparked concerns.

He was admitted to hospital twice last summer for a bladder infection, missing the last event of the queen’s diamond jubilee celebrations in June as a result. He also spent Christmas 2011 in hospital after being rushed to hospital with a blocked coronary artery, which required surgery.