The 1/5th (Derbyshire) Battalion was a 1st-Line Territorial Army formation originally serving with the 148th Infantry Brigade, part of the 49th (West Riding) Infantry Division. However, in December 1939, the battalion was reassigned to the 25th Infantry Brigade and saw service with the BEF in France and Belgium in 1940 and being evacuated at Dunkirk. In late 1940, it was again reassigned to the 55th Infantry Brigade, 18th Infantry Division. The battalion, along with the rest of the 18th Division, was posted to Malaya to defend the peninsula and the island of Singapore against the Japanese. After Singapore fell to the Imperial Japanese Army, the battalion's men were among the thousands of Prisoners of war sent to work on the infamous Burma Railway.