Remove the bones from the chicken and place them in a large pan with the water. Add 1 celery stick, 1 onion, 1 carrot and seasoning. Cover and simmer for 1½ hours. Strain the stock and keep hot.
Meanwhile, dice the chicken meat, discarding all the skin. Finely chop the remaining celery, onion and carrot. Heat the oil, add the chopped vegetables and sauté until lightly coloured. Add the chicken and cook, stirring for 5 minutes. Add the wine and cook, stirring, until it has evaporated.
Add the tomatoes and season to taste. Cover and cook over a low heat for 20 minutes, adding a little of the hot chicken stock if the mixture becomes dry.
Add the rice, then add the hot stock, a large ladleful at a time, stirring until each addition is absorbed into the rice. Continue adding stock in this way, cooking for 20 minutes until the rice is creamy.
Remove from the heat, add the butter and Parmesan and fold in gently. Cover and leave the risotto to rest for a few minutes before serving, sprinkled with parsley.