Season the lamb shanks generously with salt and pepper. Brown the lamb shanks in a large, deep oven-proof pot/pan until well-browned on both sides. Remove from the pan and set aside.
In the same pan, fry the onion, carrot, celery and garlic until soft and fragrant. Add the herbs and tomato paste and cook for 30 seconds before adding the red wine and stock. Allow to come to a simmer then add the lamb shanks back into the sauce.
Cover with a lid and place in the oven. Allow to braise slowly for 2-3 hours until the lamb is soft and succulent. Check on the lamb shanks half-way through cooking and add more stock if necessary.