This is a very unusual S&W lend lease 38 that started life as a 38 S&W and was converted by Parker Hale of England.
The barrel has been shortened, a ramp style front sight added, the cylinder changed to 38 Special, and military, plain, walnut grips and lanyard ring added.
Many, many guns were sent by S&W to England at the start of the war and different English companies turned them into military arms. Apparently Parker Hale, one of the finest firearms companies in England, did this one as it is stamped Parker Hale England on the ramp front sight. There are many British proof marks on the gun including the military acceptance "P" on the butt.