The Vintage Wrist Watch Company has dated this piece to the 1940s.
They utilised the Tissot calibre 27 15-jewel hand-winding movements, the calibre was in production from 1936 until 1949 and it was also used in the later WWW watches. This particular movement is working nicely and it has the serial number 1352682 which dates it back to 1943.

The watch measures 31mm diameter excluding the winding crown and the lugs so it is on the small side by today's standards. Some of the cases produced were chrome plated but this is the better quality stainless steel case and it is in good condition. Fixed lugs, as seen on military watches of the period.

The screw-on case back has the military pheon and the ATP markings.
The later lens is in good condition.
The dial is in its original finish... the luminous radium paint has been removed at some stage.
A new leather strap has been fitted.
The watch comes in a new presentation box.
The Vintage Wrist Watch Company has dated this piece to the 1940s.
Specialists in antique and vintage wrist watches and pocket watches
You can view the stock and full dealer information on the The Vintage Wrist Watch Company Profile Page