28th Anti-Aircraft Brigade was an air defence formation of the British Territorial Army created in 1925 to command anti-aircraft units in Kent and around the militarily important Medway Towns, which it defended during the Second World War. In 1940 the brigade was responsible for the defences on the south side of the Thames Estuary including the Royal Naval Dockyard at Chatham and the Port of Dover. The brigade was heavily engaged throughout the Battle of Britain, in the summer of 1940, and The Blitz, from autumn 1940 to spring 1941, operating a total of 70 heavy anti-aircraft (HAA) guns controlled from a gun operations room (GOR) at Chatham. During 1942 many of the brigade's experienced units were transferred to active theatres overseas. Increasingly the brigade included women of the Auxiliary Territorial Service (ATS).

55th (Kent) Heavy Anti-Aircraft Regiment, Royal Artillery was a volunteer air defence unit of Britain's Territorial Army from 1925 until 1955. In World War II it defended the Thames Estuary, Medway Towns and Dover during The Blitz and later served in Iraq and North Africa. It then supported British Eighth Army and US Fifth Army during the Sicily and Italian campaigns until the end of the war.