Heat the oil in a large saucepan over a medium heat. Add the carrots, fennel, onion, celery, garlic and bay leaves and cook for five to seven minutes. Add the cherry tomatoes, cover and cook for ten minutes. Add the ham and cook until the tomatoes are soft, then add the chicken stock and tomato juice. Bring to the boil, reduce the heat and simmer for five minutes. Cook the spaghetti according to packaging instructions, then cut into 2cm lengths and add to the broth. Bring it back to the boil, season with salt and pepper and serve.