While there is a great deal of information on British military timepieces, there is less information available on the ATP watch.
The exact meaning of the ATP acronym is still unknown, but they were supplied during WW2; and most have the following characteristics:
15 jewelled movement with a round waterproof case in stainless steel or nickel chrome, silvered dial with luminous spots and batons and luminous radioactive hands.
There were at 17 Manufacturers of these watches with 20 different variations.
Although small by the standards of today, they are reliable timepieces; however there are “fakes” of these watches appearing.