LONDON (REUTERS) - A series of handwritten notes by the late Princess Diana, one of which reveals that her younger son Prince Harry was constantly in trouble at school, is to be auctioned on Thursday (Jan 5).

The six notes, which will be sold at Cheffins auction house in Cambridge, were written to Mr Cyril Dickman who served as chief steward of Buckingham Palace for over 50 years.

Diana's sons Princes William and Prince Harry feature prominently.

One message dated Sept 20, 1984, five days after Prince Harry's birth, reads: "William adores his little brother and spends the entire time swamping Harry with an endless supply of hugs and kisses, hardly letting the parents near!..."

"The reaction to one tiny person's birth has totally overwhelmed us and I can hardly breathe for the mass of flowers that are arriving here!"

Another, dated Oct 17, 1992, says how both young princes "are well and enjoying boarding school a lot, although Harry is constantly in trouble!".

Other items being auctioned by the Dickman's family include letters, cards, and photographs from other members of the royal family, including Prince Charles, Princess Margaret, Queen Elizabeth and Prince Philip.

The entire collection is expected to raise around 15,000 pounds (S$26,532).