Young men not in uniform in 1915 were especially eager to show that they were involved in war work.
This badge has a buttonhole fixing and primarily therefore for men. It was issued to munitions workers for wear on civilian clothes.
Some larger munitions factories produced their own versions of this badge sometimes incorporating the company name.
These badges are individually numbered on the back but as far as I can find out no written record of issue survives.
| The On War Service 1916 badge has a pin fixing. I have never seen a photograph of a woman wearing the 1915 badge.
Relatively safe for dating a photograph to 1915.