 Hacket Pain re-enlisted in the British Army, and raised the 108th Infantry Brigade (part of the 36th (Ulster) Division) by recruiting the Ulster Volunteers.The Army welcomed the fact that the Volunteers were trained and armed, and Hacket Pain was appointed on 4 September to command the 108th Infantry Brigade in France.After two years he transferred back to Ireland to command the Northern Ireland district, where he served for three years.