Britain's Prince William celebrates his 30th birthday on Thursday, triggering a clause in his late mother Diana's will which could see him receive a £10 million inheritance.

The late Princess of Wales left the bulk of her estate to sons William and Harry, who were aged 15 and 12 when she died in 1997, but the executors ruled that the inheritances should not be handed over until both turned 30.

Diana left a net estate of £12,966,022, but it is estimated that the figure has grown to around £20 million through investment. Both Princes William and Harry are entitled to half of this share.

Speculation that William and wife Catherine - the Duke and Duchess of Cambridge - may use the money to buy a country house has been dampened by suggestions he is about to sign up for another tour with the Royal Air Force's Search and Rescue team.

“There has been speculation about the Duke and Duchess having a house built but there are no plans for that at all,” a royal aide told the Daily Telegraph.

“If the Duke decides next year to continue his Search and Rescue career he might well have to move to another base, away from Anglesey, so the idea of a new house just isn't on the radar at the moment,” added the official.

William and Catherine, who married last year, are expected to celebrate the milestone with friends before returning to their rented farmhouse on Anglesey, an island off the north west coast of Wales. AFP