THE Duke of Edinburgh is responding well to hospital treatment after suffering a recurrence of the bladder infection he contracted in the summer.

The 91-year-old is being treated at Aberdeen Royal Infirmary after taking ill at the Queen's royal retreat at Balmoral on Wednesday.

Buckingham Palace said he is likely to remain in hospital for several more days after being taken there by ambulance.

A spokesman said: "The Duke of Edinburgh is responding well to treatment. It is unclear when he will be discharged, but he is likely to remain in hospital for a few more days."

It follows a similar admission in May this year when he took ill after standing in the rain for a long period as he watched the Queen's Diamond Jubilee pageant on the River Thames.

He spent five days in central London's Edward VII hospital but doctors said there was no cause to be unduly concerned about the infection at that time.

It is the third time in eight months the Duke has been admitted to hospital.

In December last year, he suffered a heart scare which saw him admitted to Papworth Hospital in Cambridge with chest pains. He spent four nights convalescing at the hospital following a "minimally invasive procedure of coronary stenting".

Following the operation, Prince Harry said it had given his grandfather "a new spurt of life".

It is not known whether or not other members of the royal family were also at Balmoral or if Prince Philip has received any visitors.

Prior to his admittance to hospital, he appeared to be in good spirits as he took part in Cowes Week on the Isle of Wight.