Directly below the bell chamber and above the ringing toom is the clock room which houses a 3 train turret clock built by W. Potts of Leeds in 1893. It was installed at the same time as the bells and as part of the gift of Lady Caroline.

This is a fine piece of Victorian engineering, well worth seeing. Potts of Leeds were a major clock manufacturer and there are thousands of Potts clocks still in existence in public buildings in the UK and worldwide.

The 3 trains (gears) strike the hours, chime the quarter hours and drive the hands around the external dials on the north and south walls. The strike sequence is Westminster Chimes (the same as Big Ben). Its timekeeping is governed by a double three-legged gravity escapement.

In 1974 the clock was converted to electric motor power rather than hand wound weights. Prior to this someone had to wind it up every week. Manually winding involved placing a large crank handle on the end of a cable drum and winding a big heavy weight from the ground floor of the tower up to the clock room. As it is a 3 train clock there were 3 cable drums and 3 weights.

The clockwork mechanism still drives the hands round the dial but the weight that powers it is wound up by an electric motor.

The original chiming mechanism still co-ordinates the chimes and strikes the hours. These 2 trains are powered by direct electric motor drives.

In the photo the motors are painted blue. The left one drives the hour strike, the centre one winds the clockwork weight to power the going train, the right one drives the quarter strikes. The dial on the mechanism shows the position of the hands in minutes. There is no hour indication because the clock only provides a drive shaft which rotates once every 60 minutes. When this drive reaches the rear of the main dials an extra set of gears create the hour hand drive of one revolution every 12 hours.

Occasional adjustment is needed to keep the clock accurate as it gains (drifts) slightly so we manually stop it and start it again. It is possible to get it to run ‘spot on’ but it is affected by temperature and the forces of the wind on the dials, so it is easier to leave it running slightly fast and making occasional adjustments. The drift of a few seconds cannot be determined by looking at the outside dials. It does display accurate time.

It is serviced annually by a professional clock maintenance company.

Visits to the clock room to see the clock form part of our regular tower open days held several times a year and as part of Heritage Open Days.