Behind the faces of the Derby Cathedral clock is a history of local clock-making. It is known that a clock existed at the then parish church in 1575, and with periodic repairs continued operating until 1738. Predecessor to Smith of Derby, John Whitehurst, was entrusted with the next clock, though he did not build it. His work included fitting new tubes to support the hour hands through the 3ft (1m) thick stone walls, and for these he used carbine (gun) barrels. There was also a carillon which played tunes on the bells at timed intervals.
In 1927 the church became a cathedral, and Smith of Derby were appointed to replace the clock mechanism. A new carillon was commissioned and installed in 1931. It plays a tune once every three hours on the oldest ring of 10 bells in the world, the largest weighing in at 965kg and nearly 500 years old.
Today the clock is still in the care of Smith of Derby. As with many church dials which are painted directly on the stone surface, these can only be restored in-situ. Before the days of computer aided design, the markings were stored by Smiths as individual tracings. Now the outlines are retained on file as computer plots, enabling accurate recall of their unique patterns as well as providing a valuable (and safely backed-up) archive.