The clock in St. Mary's tower was made by J.B.Joyce & Co. of Whitchurch, Shropshire in 1890.This involved cutting the 6 foot holes through the wall and installing the mechanism inline inside. It was at that time lit by a gas mantle.
The clock has the Grimthorpe Gravity type of escapement which is famous for having first been used in the Westminster clock of Big Ben, and chimes the quarters and strikes the hours, although not in recent times. It is driven by three weights which descend 15 feet down a shaft and these were rewound by hand three times a week. It has now been converted to automatic winding and the chiming repaired.