A photograph taken by the Duke of Windsor of his brother, John - thought to be the first informal picture of the prince to be seen in public - has emerged in Paris.

Photographs show the duke relaxing with his brothers and sister in 1913 and 1914, and show the then heir to the throne as a keen photographer. One snap is of a nine-year-old Prince John dressed in a sailor suit and riding his toy car.

The album was given to friends of the Duchess of Windsor after the duke's death in Paris in 1972 and have been passed to a newspaper as other belongings of the duke are due to be sold this month in New York.

Behind the picture is the sad tale of John's life as an epileptic. He was later kept apart from the family and died at 13. He was the last of Queen Mary's five children, including the present Queen's father, and developed the illness when he was four.

In 1917, he was moved to Wood Farm, Wolferton, on the Sandringham estate, with his nurse Lalla Bill. Two years later he died.

Although the prince was kept away from visitors and housed separately, the King and Queen were not being cruel, the British Epileptic Association said yesterday. Spokeswoman Sue Mitchell said: ''There was nothing unusual in what they did. It was thought to be a form of mental illness.''