50 Pence - Elizabeth II Alan Turing

Tristan da Cunha, a British Overseas Territory of roughly 250 permanent residents in the South Atlantic, issues coins almost exclusively for the collector market — they carry no meaningful circulation function. This piece was struck to coincide with the centenary of Turing's birth year commemorations and the broader UK rehabilitation of his reputation, following his 2013 royal pardon for the 1952 gross indecency conviction that ended his career and likely his life.

The .999 silver plating over steel is a cost-reduction measure common in modern commemorative issues targeting mid-range collectors.