It has been around since the late 1800s as there was a hunting reform in 1848 upon the unification of the German states whereby the farmers and others could then hunt hooved game and not only the lords.
The effect was a fast decimation of the game as was the case in the USA.
As I understand it, it was brought in to control this overhunting. I have read of people around WW1 that had it. It works well as most all of the population accept the need for it ref weapons safety/backstop appraisal/high seat building etc, it is known as the "green high school diploma". The resistance in the UK is of course "I have been doing it for years and will not pay for a course/qualification". Accepting grandfather rights to present stalkers with DSC1 say and requiring all newcomers to do one would make sense to me. Even the USA requires all born after say 1968 to do a hunter safety course albeit a very easy one. UK is way behind in the worlds hunter qualification requirements even though they do have draconian gun laws, strange.