Unfortunately, I don’t yet have an accurate serial number by year of manufacture reference list to share. I’d appreciate copies of any such document that may be added to this page. I am able to share the following serial number guide, kindly given to me by Peter Levitt recently and by Barrie Smith many years ago. Admittedly, the numbers are a bit erratic – they do differ between NTR and Blick, and may also differ with certain models.
The serial number on most NTR wall mount clocks can usually be found on the bottom of each of the two front brass legs of the printing or clipping mechanism:
Without reliable serial number information, NTR clocks can be roughly dated by their appearance, as the models’ style changed several times during the production period. The information and images below may be used as a guide to estimate the decade of manufacture, though these are guidelines only. Many NTR clocks display features which overlap production eras, and many were refurbished with the addition of new parts and returned into service. The most simplistic rule is the more ornate the woodwork and metalwork, the older the clock – very early models can be identified by a pediment and bevelled glass.
Other clues to dating NTR clocks may be found in their labelling. In 1917, London’s postcode system changed to include a numerical suffix. This changed the NTR factory address from ‘London SE’ to ‘London SE1’, which is reflected on the address printed on the dials. This may have been phased-in over several years, but does give a rough idea as to the date of manufacture. Another useful identifier is a change of address in 1951, from London SE1 to St. Mary Cray, Kent. This address may be printed on the dial, although many old clocks had their dials replaced with new ones displaying the new address when serviced, so do be wary on jumping to any conclusions!