The Duke of Edinburgh has been taken to hospital "as a precautionary measure", Buckingham Palace said.

Prince Philip was admitted to Aberdeen Royal Infirmary while staying at Balmoral with the Queen, a spokeswoman said.

Details of the reason for his hospitalisation were not available.

It comes two-and-a-half months after he spent five nights in hospital with a bladder infection following the Diamond Jubilee Pageant on the River Thames.

The 91-year-old royal underwent a successful procedure to clear a blocked coronary artery last December and was in hospital for four nights over Christmas.

Before the heart scare he had been fit and apparently healthy, and led the active life of a man of younger years.

In March this year his grandson Prince Harry said the operation had given him "a new spurt of life".

He was forced to miss some of the jubilee celebrations in June after he was admitted to hospital the day after braving the elements for the pageant.

Prince Philip was at the Queen's side during the Opening Ceremony of the London Olympics on July 27 and the following when they toured the Olympic Park.

While in Scotland earlier this month he supported the Queen at engagements including hosting a tea party at Balmoral to mark the end of her Diamond Jubilee celebrations.