This Post Office wall clock, introduced in 1970, was designed for use in GPO offices and exchanges. It features a distinctive 13 to 24 hour dial for use where operations were based on 24 hour timings. It did not have its own power source but operated on an electrical impulse generated every 30 seconds by a master clock - hence the term ‘slave’. The master clock would be wired to a number of slave clocks, ensuring accuracy and consistency across the series.
The flat glass, aluminium dial and steel falseplate with integral hanging bracket are secured in a spun aluminium case by spring clips. The original polychromatic silver-grey finish to the case was badly scratched and degraded, so it has been professionally repainted in satin black. The original pulse movement (which could not operate without a master clock or other pulse generator) has been replaced with a high quality German UTS quartz movement. The hands are original to the clock and have been re-colleted to fit the arbors of the new movement..
This example, which bears a stamped date of 28 January 1975, is in excellent overall condition and full working order (it takes a single AA type battery).