London, June 16 A large desk rubber used by Diana, Princess of Wales, at her boarding school is set to go under the hammer and is expected to fetch more than 300 pounds.

The 5ins x 2ins eraser, which is marked with the words 'For BIG mistakes', will be auctioned off at Reemans Auctioneers in Colchester, Essex on June 23, reports The Telegraph.

It was kept in the future Royal's pencil case and she used it as a nine-year-old schoolgirl during lessons at the all-girl Riddlesworth Hall preparatory school in Diss, Norfolk.

The Princess personalized it with the words "D.Spencer", "Diana" and "Riddlesworth Hall", and "Diss" in her own handwriting. (ANI)