When war broke out the only insignia worn on uniforms was shoulder titles and cap badges. Divisional symbols / insignia existed after the first few months and were painted on vehicles / buildings etc. As the war progressed to thwart enemy intelligence and to make units more identifiable battalion badges / patches were introduced and took the form of symbols / geometric designs images etc.

By the end of the war units could be seen with patches unique to their battalion, brigade patches and Div patches. Worn on uniforms ( upper sleeves, back of tunics below collar and on helmets).

Not every unit had them and not all have been recorded.

Cap badges and shoulder titles were never discarded though. For raids these metal titles badges were removed and the cloth patches would ID a soldier to a friend but not the enemy.

My thanks to Jan Snell for providing the above badge.