The Turret Clock is of open construction and has an anchor escapement It has two drive trains, one for the chime which strikes the hour and one for the hands.
The pendulum “ticks” 47 times a minute. The chiming train runs for 7 days and two hours before the weight hits the floor and the going train rings for 8 days. Each train is driven by a separate weight which is hand wound once a week.. The weights are iron with lead sheathing. The one for the going train is very old and possibly the original.
It is believed that it was originally a 30 hour one hand clock chiming only once every hour and that it was converted to its present form in 1729. There are some redundant holes in the frame to support this belief The time indicator has an inscription “REPAIRED BY JOHNBRIANT HERTFORD 1780
The drive mechanism for the hands was refurbished, bushes replaced and new brass hands made in 1984 by apprentices of British Aerospace (formerly de Havillands)
It has one face, on the north wall of the tower which is square and mounted as a diamond. The face is made of wood with gold leaf roman numerals. This face was renewed in 1995 to replace, to the exact same design and size, the face which was probably installed in 1904 by Earl Cowper At this time the brass hands were gold leafed by the apprentices at Bedford college who also did the gold leaf numerals.