The British advance in pursuit of the German army in early 1917 as it withdrew to stronger positions on the Hindenburg Line brought a brief resumption of mobile warfare, and from the experience GHQ emphasised the need to get all light weaponry as far forward as possible to support infantry, and that "Covering fire of 18-pounders and 4.5-inch howitzers can not be too far exploited" should be exploited as much as possible. It also warned "There was tendency, due to trench warfare, among C.R.A.s to attempt to control individual batteries. Brigade or group commanders should be given a task and allowed to carry it out".