The Brigade played a vital role in the defence of the United Kingdom during the first year of the Second World War, including guarding aerodromes and other vulnerable points. In May 1940, due to the withdrawal of the British Expeditionary Force (BEF) from France and the increased threat of invasion, a Brigade force known as the Yeomanry Armoured Detachment was formed to defend the coast of East Anglia, concentrating at Moulton Paddocks, Newmarket as a counter-attack force to repel any potential Nazi offensive.