Is this jacket military surplus?

Hi from Atlanta. I got this jacket at an Army/Navy store that carries uniform items, current and outdated, from the U.S. and other countries. I'll use it as a tough raincoat, and it said "BRITISH" on the store tag. Is it military issue? And if so, from where?

In the pocket was a receipt printed with the word "Barnado's" (a UK charity).

Can't find any pictures of it. It has the epaulette loop thingies on the shoulders, and it's pretty heavy duty. Darker green than the U.S. olive drab. Any input much appreciated.
Here's some pictures of it: https://imgur.com/a/xx5fr

I would be inclined to say it is a civilian jacket based on the tag, but?
Sarge