The British army introduced the Bren light machine gun in 1937. The gun was standard issue for British and Canadian infantry units during the Second World War. Each infantry group was equipped with one Bren gun group for local automatic support fire. Designed to be portable, the use of the Bren gun meant that tactics could include fast-moving automatic fire. This was a great improvement over the older Lewis light machine gun whose weight and dimensions prevented it from being used in an attack at speed. Also used as an anti-aircraft weapon, the Bren gun played an important role in attacking German planes during the Battle of Britain.