Preheat the oven to 190C/375F/Gas 5. Place a large casserole dish over a high heat on the hob, add the olive oil and when hot, add the chicken to the dish. Cook, turning occasionally, until brown all over. Remove from the dish and set aside.
Add the bacon to the casserole dish and fry for a 2-3 minutes, until golden. Add the celery, carrots, potatoes, thyme and bay leaves.
Pour in the chopped tomatoes, add the Worcestershire sauce and stir. Add the chicken stock and return the chicken to the casserole dish.
Bring to the boil, season with salt and freshly ground black pepper, then put the lid on the casserole. Transfer to the oven to cook for one hour, or until the chicken is tender and completely cooked through.
To serve, remove and carve the chicken breasts on the diagonal. Spoon the vegetables and broth into bowls and top with the sliced chicken.