Probably supplied to Adolphus, 1st Duke of Cambridge on his creation as GCMG. The date letter of the hallmark is poorly struck but may be ‘h’ (1823-4) or ‘k’ (1825-6). An almost identical badge, hallmarked 1823, is in the Royal Collection and is described and illustrated by Stephen Patterson, Royal Insignia, London, 1996 (catalogue no. 90, ‘probably belonging to King William IV’). It may be noted that the obverse of the same piece is in addition illustrated by Peter Galloway, The Order of St Michael and St George, London, 2000 (pl 4, lower left, although Galloway’s attribution of that particular Royal Collection badge to ‘Prince Adolphus Frederick, Duke of Cambridge’ appears to be incorrect).