The British Army was content with its .455 Webley Mk VI revolver, but as World War I (The Great War) loomed on the horizon, it became clear that Webley could not keep pace with the rapid mobilization.
In 1914, the British Purchasing Commission approached the American company of Smith & Wesson, of Springfield, Massachusetts. Their proposition was to grant S & W license to manufacture the .455 Webley revolver for British use. Smith & Wesson countered with another proposal. Tooling up to make the Webley would prove too costly, and time consuming. Rather, allow S & W to make their New Century revolver in caliber .455 for British consideration. The Purchasing Commission asked for samples, which S & W promptly made up.
Upon examination of the revolver, the British asked two changes to be made: eliminate the third lock at the yoke, as being unnecessary, and a cost saver. Also, eliminate the locking lug extension that enclosed the ejector rod, as it might possibly clog with mud, preventing closing the revolver. Smith & Wesson complied with these requests and a contract was agreed upon. Smith & Wesson was to supply 75,000 of these revolvers to the British Government, and they saw action both in World War I and World War II. No Korean era information is at hand. These guns were declared surplus in the 'fifties and most were returned to dealers in the U.S. who sold them off by mail order for prices ranging from $19.95 to $34.95 until GCA '68 put a stop to that practice.
Incidentally, since 1914, all Smith & Wesson revolvers designated Army Model or Military and Police Model have had the short under barrel locking lug introduced on these British service revolvers. And, it was this revolver that was the basis for the M1917 .45 ACP revolvers made for the U.S. Government about the same time period.