If this technology ever does prove to save lives on the battlefield, it would only be the lives of the "good guys". The lives of the opposing side would be destroyed with ever-increasing efficiency.
Of course, if you believe that the foes that Britain will face in the foreseeable future are intrinsically evil and deserve to be destroyed with ever-increasing efficiency, then this is fine. If you believe that destroying lives full-stop with ever-increasing efficiency is ok, that this is fine.
Another way to help save thousands of lives on the battlefield would be not illegally invade sovereign countries with thinly-veiled justifications designed to cover up one's own economic and emperial ambitions.