Making a portrait of Diana, Princess of Wales in the 1990s was one of the happiest and memorable highlights of my work. It was also challenging because the Princess had the most well known face in the world. Throughout the course of the sittings, I was humbled by her kindness, interest, generosity and affection.

The commission was for the new wing of the National Hospital of Neurology and Neurosurgery, Queen Square, London. The Princess was the Patron of the Hospital and she unveiled the bronze sculpture in 1992.

A letter from Buckingham Palace informed me that there would be a total of four sittings with the Princess, each lasting one hour. The great portrait sculptors like Rodin worked with the sitter every day for a month. The Palace’s prescribed number was daunting and I was extremely worried about getting a good likeness with so few sittings.

From the beginning my main interest was expressing the humane spirit of the Princess and how to do her justice in clay. I was intent on using no jewellery on the portrait because I wanted to communicate her natural warmth and beauty without any artifice.

During the sittings the Princess was happy, inquisitive, relaxed and asked many questions about myself. At the end of the fourth and last scheduled sitting the Princess asked if I would like another sitting. This came as a complete surprise and I accepted it most gratefully. From then on the same thing happened at the end of each sitting that followed. I never knew which sitting would be the last and I always felt like I was in a precipitous state of grace as I worked on the clay. In the end I had ten official sittings and two short unofficial, but useful sittings. The Princess came to view the final clay state of the portrait and I was glad to get the Princess’s final approval before I sent it for bronze casting.