The battalions, like all other TF battalions, were redesignated with the '1/' prefix (1/4th Ox and Bucks, for example) to distinguish them from the 2nd Line units, formed of those men who did not originally volunteer to serve overseas, who were designated with the '2/', and were later numbered 184th (2/1st South Midland) Brigade, 61st (2nd South Midland) Division.

The 145th Brigade, with 48th Division, later pursued the German Army in the retreat to the Hindenburg Line and again fought in the Battle of Langemarck and later at Polygon Wood, both part of the Passchendaele and later on the Italian Front until the Armistice in 1918 with Germany.

The Second World War began on 3 September 1939, although the division had been mobilised two days earlier, along with the rest of the Territorial Army due to the German invasion of Poland.

[5] In early January 1940 the 145th Brigade, commanded at the time by acting Brigadier Archibald Cecil Hughes, and the rest of 48th Division, was sent to France in early January 1940 to join the rest of the British Expeditionary Force (BEF) which was stationed on the Franco-Belgian border, alongside the French Army.

[5] The brigade, with the rest of the 48th Division, fought in the battles of Belgium and France, and at the battle of the Ypres-Comines Canal and had to retreat to Dunkirk be evacuated to England after the German Army threatened to cut off the entire BEF from the main French Armies.

With the rest of the division, the brigade was stationed in Cornwall on home defence, anticipating a possible German invasion which, fortunately, never arrived due to the attempt to gain air superiority which failed during the Battle of Britain.

In late December 1942 the division and brigade were reduced to a Lower Establishment and became a training formation in the United Kingdom.