100 Pounds - Elizabeth II 4th portrait, 1 oz Fine Gold

The 2013 date places this coin in the transitional period following the Royal Mint's relocation from Tower Hill in London to Llantrisant in Wales — a move completed in 1980 but whose downstream effects on production capacity made the expanded bullion program of the 2010s possible. The Britannia series shifted to .9999 fineness that same year, up from the previous .9167 standard, a change driven partly by competitive pressure from the Canadian Maple Leaf and Austrian Philharmonic.

Ian Rank-Broadley's fourth portrait, used here, was introduced in 1998 and remained current until Jody Clark's effigy replaced it in 2015.