The clock originally occupied the lower part of the tall arch-headed opening immediately above the roundel at the base of the tower. (The stone roundels at the base of the tower may have been intended to house the clock-dials.) It was destroyed by the fire of 1836 and replaced by an eight-day clock supplied by J P Paine. In 1866 clock dials illuminated by gas were installed in their present position higher up the tower.