“Close-order drill” — guarding Buckingham Palace — is not the only kind of drill. Soldiers are drilled in a second kind, variously called combat drill, extended order drill, or skirmishing.
All drill is about collective discipline, obedience, and teamwork, but close-order drill runs the risk of developing “want of elasticity … and work by rule”(1). Actually, the source I quote doesn’t speak of running a risk, but says that “stereotyped formation” close-order drill “inevitably leads to want of elasticity and work by rule” (emphasis added.) Close-order drill denies to all ranks the “exercise of their wits,” and “cramps both initiative and intelligence.” (1)
Combat drill, on the other hand, requires both initiative and intelligence — or at least, “all ranks must act to a large extent independently in carrying out orders [since] very few rules can be prescribed.” (2)
His Majesty’s Infantry Training Guide strictures on skirmishing are (obviously) directed at infantry, not artillery, but when batteries are called out to action in mobile warfare the principles are the same. (3)
Under the stress of actual combat, of course, “a spirit of independent action” is sorely tested. Such was the case when infantry charging across No Man’s Land found barbed wire that had not been cut as promised. Obedience to orders in the heat of battle meant that they charged in waves upon the non-existent gap, and were slaughtered, hung up on the wire.
(1) Infantry Training. London 1905. 25
(2) page 17
(3) page 54.