DUBAI, Nov 22 (Reuters) - Britain and Gulf Cooperation Council (GCC) countries are negotiating a free-trade agreement, Britain"s investment minister, Gerry Grimstone, said on Monday. A deal will be concluded within 12 months, Grimstone said at a conference in Dubai. The GCC is already an important trading partner for Britain, with almost 22 billion pounds ($29.57 billion) of British exports and bilateral trade worth over 30 billion pounds in 2020, showed a British government website. ($1 = 0.7440 pounds)