The clock and dials were designed by Augustus Pugin. The clock dials are set in an iron frame 23 feet (7.0 m) in diameter, supporting 312 pieces of opal glass, rather like a stained-glass window. Some of the glass pieces may be removed for inspection of the hands. The surround of the dials is gilded. At the base of each clock dial in gilt letters is the Latin inscription:
DOMINE SALVAM FAC REGINAM NOSTRAM VICTORIAM PRIMAM