 Arriving in France on the Western Front in January 1916, McCreery found that his regiment, serving as part of the 5th Cavalry Brigade, had recently begun to operate in the infantry role in the trenches, although retaining the capability of reverting to cavalry should the need arise.This they did in preparation for the Battle of Arras in April 1917, where the 12th Lancers and the rest of the 5th Cavalry Division formed a cavalry reserve in case there was a major breakthrough which could be exploited.On 10 April, the cavalry moved up behind the advancing British infantry near Telegraph Hill and were kept in an exposed position overnight.