This is one of the only British firearms that I’ve ever wanted to own, mainly because it is such an interesting piece of technology.

The Lee-Enfield rifle started life in 1888 as the Lee-Metford rifle, combining Mr. Lee’s cocking technology with Mr. Metford’s rifling. However, as smokeless powder overtook black powder as the propellant of choice, it was discovered that Mr. Metford’s rifling system was inadequate and quickly wore away with repeated use. Mr. Enfield designed a more robust rifling technique, and the Lee-Enfield began introduction about 1895.
What makes this weapon particularly interesting to me is that the firearm is cocked when the bolt moves forwards.

On most rifles, the action of opening the bolt is what causes the firing pin to **** backwards. The Mauser action was one of the first to use this system, and the U.S. m1903 rifle followed suit with a similar system. The effect was that it was much more difficult to open the bolt than to close it, and required more force and more leverage. With the SMLE the bolt cocked back as the bolt went forward, meaning that when opening the bolt the action nearly springs open with very little assistance. This development made the gun very quick to cycle and meant that (with the exceptionofa straight pull bolt like the Schmidt Rubin) it was and probably still is the fastest bolt action design on the battlefield.

The name of the design, specifically the “short” part, refers to the barrel and not the magazine. The magazine size has remained constant since the initial development of the rifle, holding 10 rounds of ammunition typically loaded via stripper clips. It’s a common misconception that the “short magazine” is all one phrase, indicating the magazine had been shortened.

I’m fairly certain that this is the Mk. III (I have to admit I don’t watch these shows live), but based on the length of the barrel and the shape of the cocking piece it looks like a smelly mark three to me.