In December 1935 the TA's 46th (North Midland) Division (which also acted as HQ for the North Midland Area of Northern Command) was disbanded and its headquarters was converted into 2nd Anti-Aircraft (AA) Division to control the increasing number of AA units being created.

At first it administered all AA units in Great Britain outside London and the Home Counties, which were covered by 1st Anti-Aircraft Division.

[4] In 1938 the Royal Artillery replaced the traditional unit designation 'Brigade' by 'Regiment', which allowed the AA Groups to take the more usual formation title of Brigades.

[8] They were replaced in the 2nd AA Division by new brigades created in September 1938: the 39th at Retford in Nottinghamshire and the 40th and 41st in London.

[6][11] The deterioration in international relations during 1939 led to a partial mobilisation in June, and a proportion of TA AA units manned their war stations under a rotation system known as 'Couverture'.

The number of LAA units to protect Vital Points such as airfields was growing, albeit slowly.

The increased sophistication of Operations Rooms and communications was reflected in the growth in support units, which attained the following organisation by May 1942:[33] The RAOC companies became part of the new Royal Electrical and Mechanical Engineers (REME) during 1942.