British re-armament was a period in British history, between 1934 and 1939, when a substantial programme of re-arming the United Kingdom was undertaken. Re-armament was deemed necessary, because defence spending had gone down from £766 million in 1919–20, to £189 million in 1921–22, to £102 million in 1932.

Royal Ordnance Factories (ROFs) were munitions factories run by the UK government during and after the Second World War. The three main types of factories were engineering, filling and explosives, and these were dispersed across the country for security reasons. ROFs were the responsibility of the Ministry of Supply and later the Ministry of Defence until privatisation in 1987.