the Plymouth and Falmouth Defences of Southern Command. On 1 January 1939 the RA replaced its traditional unit designation 'Brigade' by the modern 'Regiment'. Anti-Aircraft Command was formed in April 1939 to command all TA air defences. The Blitz By the outbreak of the World War II, 56 AA Regiment was part of 35th Anti-Aircraft Brigade in 5th Anti-Aircraft Division of AA Command. On 1 June 1940, along with other AA units equipped with the older 3-inch and newer 3.7-inch AA guns, the 56th was designated a Heavy AA Regiment. By then the regiment had been transferred to the command of 55th Anti-Aircraft Brigade in 8th Anti-Aircraft Division. This brigade provided air defence for the city of Plymouth and its Royal Navy Dockyard during The Blitz. The regiment provided the cadre for a new 381 HAA Bty formed on 14 November 1940 at 205th HAA Training Rgt, Arborfield, which later joined 120th HAA Rgt. It provided another cadre for 458 (Mixed) HAA Bty formed on 10 July 1941 at 207th HAA Training Rgt, Devizes, which joined 131st (Mixed) HAA Rgt. ('Mixed' units were those in which women of the Auxiliary Territorial Service (ATS) were integrated.) In May 1941 the regiment joined the War Office Reserve, while still remaining part of 55th AA Bde. This mean that it was being prepared for service overseas. At the same time, 203 Battery was detached. Iceland In July 1941, 203 Battery was sent to Iceland, which had been occupied by British forces ('Alabaster Force') the previous year. The battery came under command of the Regular 12th HAA Regiment and was stationed to protect Royal Navy and Royal Air Force installations. However, the decision to transfer the defence of Iceland to the (still neutral) United States had been taken in July 1941, and the AA positions were taken over by US forces later in the year. India In December 1941 the regiment sailed (with 165, 201 and 202 Batteries) to India, arriving at Madras in March 1942, 202 Bty moving on to Calcutta shortly afterwards to join 53rd (City of London) HAA Rgt. In 1942 56 HAA was under command of 13 AA Bde; a year later it was part of 3rd Indian AA Bde, which then exchanged with 9 AA Bde, all in the Bombay and Madras area. It also had 154 (London) Battery from 52 (London) HAA Regiment, which joined on 29 March