Place stock and bay leaf in a large saucepan and bring to the boil. Add chicken and carrots, reduce heat to very low, cover and simmer gently for 5 minutes. Add leeks and peas, simmer for a further 2-3 minutes or until chicken is cooked through. Remove and slice the chicken, and place in four shallow bowls. Spoon over vegetables and a little stock, garnish with parsley and season with freshly ground black pepper.