This is an original, British military, Denim Overalls Blouse. It is in unissued condition. Throughout WWII, the British military was issued a set of denim overalls like this in order to protect their more expense wool battledress uniforms while performing dirty work duties. That being said, these are a bit oversized. Later they became a popular lightweight summer uniform in lieu of the woolen suit, when permitted. This design was issued from around 1939 until the 1960's when it was phased out. Our examples here are all Size 9 and dated 1951.