Five letters written by the author Lewis Carroll shortly before his death have been found in a locked journal and are being hailed as an important literary discovery.

The letters, written in 1896 and 1897 were unearthed by archivists in Alnwick castle, Northumberland.

Carroll, who wrote Alice's Adventures in Wonderland, was a friend of the 7th Duke of Northumberland. One of the letters is to the duke's daughter, Muriel.

A spokesman for the 12th duke said today: "We think it is exciting as the final letter was written so close to his death and was signed Lewis Carroll as opposed to his real name, Charles Dodgson.

"We have to remember Carroll's books were the Harry Potters of their time and for the seven-year-old Muriel to have received such a letter must have been wonderful."

Mark Richards, chairman of the Lewis Carroll Society, said: "The letters will help to fill in certain gaps in the jigsaw of his life."

The letters are on display at the castle until October.