No. 11 Group is a group in the Royal Air Force first formed in 1918. It had been formed and disbanded for various periods during the 20th century before disbanding in 1996 and reforming again in 2018. Its most famous service was in 1940 in the Battle of Britain during the Second World War, when it defended London and the south-east of the United Kingdom from attacks by the German Luftwaffe. It was reformed in late 2018 as a "multi-domain operations group" to ensure the service thinks and acts in a networked way.