The fifth crowned portrait of HM Queen Elizabeth II facing right, wearing the George IV State Diadem and drop earrings.

The George IV State Diadem, officially the Diamond Diadem, is a type of crown that was made in 1820 for King George IV. The diadem is worn by queens and queens consort in procession to coronations and State Openings of Parliament. The piece of jewellery has been featured in paintings and on stamps and currency. It can be seen in the Queen's Gallery at Buckingham Palace.

ELIZABETH II DEI GRATIA REGINA FIDEI DEFENSATRIX means Elizabeth II, by the grace of God, Queen and Defender of the Faith.

Engraver: Jody Clark

Depicts the name ‘Babbage’ in lowercase, extending the ascenders and descenders on the letters ‘b’ and ‘g’ and using a geometric modernist typeface started to suggest the levers and cogs seen in the difference engines, accompanied by numbers representing the name Babbage in numerical code.

A difference engine is an automatic mechanical calculator designed to tabulate polynomial functions. It was designed in the 1820s, and was first created by Charles Babbage. The name, the difference engine, is derived from the method of divided differences, a way to interpolate or tabulate functions by using a small set of polynomial co-efficients. Some of the most common mathematical functions used in engineering, science and navigation, were, and still are able to be computed with the use of the difference engine's capability of computing logarithmic and trigonometric functions, which can be approximated by polynomials, so a difference engine can compute many useful tables of numbers.

Engravers: Nigel Tudman and Jas Bhamra