HC Deb 04 April 1938 vol 334 c24
49. Colonel Nathan

asked the Postmaster-General what measures are taken and at what intervals to check the accuracy of weighing machines in post offices?

Major Tryon

Automatic letter scales are tested daily by means of test weights, and automatic parcels scales once a fortnight by the same means. Scales other than those of the automatic type are tested less frequently, but sufficiently often to ensure against inaccuracies.