The obverse portrait of the Queen by Ian Rank-Broadley was used on all UK coinage from 1998 to 2014 and also on some coins dated 2015. It was the fourth portrait of the Queen used on coinage.
The reverse design, by Tom Phillips shows parts of the dictionary definitions for the words ‘Fifty’ and ‘Pence’. Under this is ‘JOHNSON’S DICTIONARY 1755’. Samuel Johnson’s famous dictionary of 1755 contained 40,000 words and took eight years to complete:
2005 Johnson's Dictionary