It comprised anti-aircraft (AA) 'brigades' of the Royal Artillery (RA) and AA battalions of the Royal Engineers (RE), but when the RA redesignated its brigades as regiments in 1938, the group adopted the more usual title of 32nd (Midland) Ant-Aircraft Brigade in November 1938.

On the outbreak of war its order of battle was as follows:[4][5][6] In 1940 the RE AA battalions were transferred to the RA, and that summer the AA regiments of the RA were redesignated Heavy Anti-Aircraft (HAA) to distinguish them from the new Light Anti-Aircraft (LAA) units being formed.

AA Command redeployed its S/L units during the summer of 1941 into 'Indicator Belts' of radar-controlled S/L clusters covering approaches to the RAF's Night-fighter sectors, repeated by similar belts covering AA Command's Gun Defence Areas (GDAs).

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

[26][27][28] Newly formed units joining AA Command were increasingly 'mixed' ones into which women of the Auxiliary Territorial Service were integrated.

5 AA Group had to reorganise its defences, stripping HAA guns from inland sites and moving them to the coast of East Anglia.

[23][42] AA Command was also suffering a personnel shortage, as fit men were posted to make up losses in 21st Army Group fighting in North West Europe.

[23][40] It was briefly joined on 1 January by 72nd (Middlesex) S/L Rgt at Hatfield Militia Camp near Doncaster, which consolidated the personnel of 72nd, 80th and 82nd S/L Rgts while they awaited posting elsewhere.