Two Hundred and Fifty Pounds Britannia 2017 20oz. of .999 silver, 20th Anniversary of the minting of the First Britannia Silver coins S.BJ1, Reverse: Britannia holding a shield and trident, her body combined with the United Kingdom and the inscription BRITANNIA 20 OZ. FINE SILVER 999 2017, with Trident Mintmark. Reverse design by Louis Tamlyn, currently the only issue of this unusual denomination. In a large NGC holder and graded PF69 Ultra Cameo