9 carat is 37.5% pure. Divide weight in ounces by 2.6666, multiply by .911 to get the amount of pure gold in troy ounces, and compare to current gold price.
It depends how much it weighs and if it has any gems or diamonds in it. Since it's not really worth very much with just the gold alone (£10.58/gram) you might want to consider selling it online where you may get more for it than you would in a pawn shop.