The St Paul's website tells us about the clock and associated bells:
The Clock
The clock dates from 1811, predating the present tower (1867 by Palgrave). It is the largest clock in north Bedfordshire with four, eight foot dials. The maker is John Moore and Sons of Clerkenwell, London. The movement has a deadbeat escapement.
The clock originally played ‘ding dong’ quarters on two bells, striking the hour on the tenor bell. In 1908 John Bull & Co of Bedford converted it to play the Cambridge quarters (or the Westminster chimes as they later became known, when used for Big Ben).
The quarters strike on bells number 6, 7, 8 and 11 whilst the hours are struck on the 12th (Tenor bell). The clock was converted to electric winding in 1959 with an automatic cut-out to prevent over winding.
In 2002, thanks to a legacy by Winifred Hall, the quarter chimes and hour striking mechanisms were restored after nearly thirty years of silence; thus making St. Paul’s an aural as well as a visual presence in the centre of Bedford. The clock had a major overhaul during 2008.
The Carillon
The carillon, a mechanism for automatically playing tunes on the bells was made by Gillett and Bland in 1879 and was purchased by public subscription.
It played tunes every third hour starting at 9.0 a.m. with a cut-out at night. There are several barrels which were changed weekly, playing hymns on Sundays and secular tunes during the week. Amongst its repertoire were Home Sweet Home; Barbara Allen and Drink to me Only.
On Barrel 1 is the Sunday Hymn tune ‘Bedford’ composed by William Weale c.1720 who was then organist of this church.
This rare machine is now derelict, being last heard in the 1960s, when the connection to the bells was dismantled.