Often, the emphasis with military history is on the fighting arms involved, the infantry, tanks, artillery, engineers and signals, but as the proverb about the battle being lost for the want of a nail well demonstrates, there was (and still is) much more to fighting a battle and prosecuting a success military campaign.
The fighting soldiers have to be properly equipped, fed, provided with sufficient ammunition to fight a battle; plus they need and deserve to paid the correct amount and on time. If they are injured, they need prompt and professional medical care. Their spirital needs have to be catered for.
All these vital and yet unglamorous functions and activities were the responsibility of the various Services of the British Army. Each had a key role to play in the war, without which the army could not fight effectively.