The 171st Field Regiment was a unit of Britain's Royal Artillery (RA) during World War II. Originally formed to man beach defence batteries, it later became field artillery and briefly converted to heavy artillery. It served in Home Forces and supplied trained gunners to the fighting fronts, but saw no active service. It was disbanded after the war.

The 45th Infantry Division was an infantry division of the British Army, formed just prior to the start of the Second World War. In March 1939, after the re-emergence of Germany as a significant military power and its occupation of Czechoslovakia, the British Army increased the number of divisions in the Territorial Army (TA) by duplicating existing units. The 45th started forming in August 1939 and became active the following month, as a second-line duplicate of the 43rd (Wessex) Infantry Division. The division's battalions were all raised in the West Country.