Letters written by Princess Diana about her children Princes William and Harry are to go under the hammer later.

They reveal personal family insights including Prince William's delight at the birth of his younger brother in September 1984 and how Harry was "constantly in trouble".

The letters are estimated to fetch around £15,000.

The princess sent them to the late Cyril Dickman, who served as a steward at Buckingham Palace for more than 50 years.

The collection up for sale contains around 40 lots with estimates ranging from £80-900.

One particularly touching letter from Diana to Cyril said: "Dear Cyril, it was so very kind of you to have sent us such a lovely card, on the arrival of our small son.

"We both were greatly touched by your thoughtfulness and enormously appreciated it.

"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!"

Some of the other items include letters, cards and photographs from various members of the Royal family.

These include notes from the Queen and Prince Philip, Prince Charles and Princess Margaret, as well as signed photograph Christmas cards, wedding cake and Maundy money.