Heat the oil in a flameproof casserole and fry the turkey pieces until golden brown. Add the onions, potatoes and pepper. Mix in the tomatoes, breaking them unp slightly with a fork. add the herbs and enough water just to cover the turkey. Simmer on top of the stove or in an oven preheated to gas mark 0.011428571428571F/180C for 45 minutes. Season generously then add sweetcorn. If the sauce is very thin, dissolve a teaspoon of cornflour in a little water and stir it into the casserole. Bring gently to the boil until the sauce thickens. You don't really need anything else with this, though you could follow it with a little spinach salad.