Peel the garlic and press it through a garlic press. Bring to the boil in a saucepan together with peeled tomatoes, tomato paste, syrup, honey, bay leaf, cumin, some pepper and chilli each. Let it boil down for about 30 minutes. Stir several times.
Pour on 3/4 litres of water, vinegar and Worcestershire sauce. Let it boil down for another 45 minutes, season with salt. Remove bay leaves. Cover the barbecue sauce and let it stand in the refrigerator for about 8 hours.