LONDON — Prince Philip, the 91-year-old husband of Britain's Queen Elizabeth, was taken to hospital in Scotland on Wednesday as a "precautionary measure," Buckingham Palace said, the third time he has been hospitalized in less than a year.

Philip, the Duke of Edinburgh, fell ill while the couple were staying at Balmoral, their Scottish royal residence, and the BBC reported he had been driven the 40 miles from there to hospital, suggesting the problem was not too serious.

"He was taken to Aberdeen Royal Infirmary as a precautionary measure," a Palace spokeswoman said. "We don't have any further details and are waiting for the Duke to be medically assessed."

Despite recent illnesses, the sprightly Duke has continued to make public appearances, notably at events held to mark the queen's 60th year on the throne this year.

The BBC said his last public engagement had been at Cowes in the Isle of Wight off southern England earlier this week.

During the London Olympics, he accompanied the queen to the opening ceremony and also joined other members of the royal family to watch granddaughter Zara Phillips compete in an equestrian event at the Games.

He was hospitalized two months ago when he received treatment for a bladder infection, overshadowing four days of public celebrations for his 86-year-old wife's Diamond Jubilee.

Days earlier he had braved wind and rain to watch a 1,000 boat flotilla on the River Thames from a royal barge before falling ill and being unable to attend a thanksgiving service at St Paul's Cathedral.

In December last year, Philip had an operation to clear a blocked artery in his heart after suffering chest pains, and spent four days in hospital over Christmas.

Philip, the longest-serving consort in British history has won admirers for his charity work and loyal support to the queen, but is as well-known for his sharp wit and verbal gaffes as he is for his devotion to duty.

A stray remark about "slitty eyes" during a visit to China in the 1980s became symbolic of the Greek-born former naval officer's gruff and often unguarded manner.

Son of the exiled Prince Andrew of Greece, Philip married Princess Elizabeth, as she was then, in 1947.

They met when she was 13 on a visit to the naval college where he was a cadet. Following World War Two they became engaged, and he was given the title of the Duke of Edinburgh.