2 carrots, cut in half
1 stalk celery, including the leaves, roughly chopped
1 whole head garlic
2 leeks, cut in half
3 onions, unpeeled
large bouquet garni of parsley, sage and thyme
1 tbsp peppercorns
1 tsp sea salt
2-2.5kg/4lb 6oz-5lb 8oz of beef bones (rib, leg marrowbones - you can buy these from your butcher)