William, Prince of Wales, followed me through the house, pen and paper in hand. Ignoring the antique furniture, he was most interested in the pictures – and completely oblivious to the mess in all the rooms.

This was so much fun that I forgot that I hardly knew this man and laid my hand on his arm. When I realised my mistake, the Prince winked at me. There was apparently no need to apologise for my breach of royal etiquette.