Watch List notes:

BRITISH COINS, George IV (1820-1830), Bronzed-copper Trial Farthing, 1821, first laureate and draped bust left, legend spaced so IA. ends under drapery, rev inverted die axis, Britannia seated right with trident and shield, date and stop in exergue, legend closely spaced so final colon farther from lion's face, 4.68g (Peck 1418 EXR; S 3822). Dark chocolate coloured tone, small spot by forehead, otherwise practically as struck and extremely rare.
ex St James's Auction 9, 18 June 2008, lot 673 (described there as a regular proof, Peck 1408)

Estimate: £1800-2200