LONDON (AFP) - Britain's Prince Philip is doing "much better", his son Prince Charles said after visiting the 92-year-old in hospital on Friday, one week after he underwent exploratory surgery on his abdomen.

Heir to the throne Charles, the eldest son of Philip and Queen Elizabeth II, visited the private London Clinic with his wife Camilla and his sons, Princes William and Harry.

Wearing a grey double-breasted suit, Prince Charles smiled and waved to the waiting media as he emerged after the half-hour visit. Asked how his father was, he replied: "Much better."

Earlier in the day, Princesses Beatrice and Eugenie also went to visit their grandfather, who was said by the palace on Monday to be "comfortable and in good spirits" following his operation.

The duke of Edinburgh was admitted to hospital on June 6 and underwent planned surgery the following day.

The palace has not said why he needed the operation, only that it followed abdominal investigations in the days before.

He is expected to remain in hospital for two weeks, and will take two months to convalesce.

The 87-year-old queen, who married Prince Philip in 1947, visited her husband on Monday and stayed about half an hour.