The British Army's 148th Infantry Brigade mobilised as part of 49th Infantry Division on 1st September 1939. Most of the Division had not undertaken sufficient training and was poorly equipped. Because of this, they suffered heavy casualties in the Norwegian Campaign of early 1940.
When most of 49th Infantry Division went to Iceland in the summer of 1940, 148th Infantry Brigade made the journey to Northern Ireland. Later redesignated 148th Independent Infantry Brigade, they fell under the command of British Troops Northern Ireland from 7th July 1940 to 26th April 1942.