page_title: 91st Heavy Anti-Aircraft Regiment, Royal Artillery
section_title: Mobilisation
hierarchical_section_title: 91st Heavy Anti-Aircraft Regiment, Royal Artillery / World War II / Mobilisation
caption_attribution_description: English: 3.7 inch anti-aircraft gun at Fort Paull, Paull, East Riding of Yorkshire, England
context_page_description: 91st Heavy Anti-Aircraft Regiment, Royal Artillery was a part-time unit of Britain's Territorial Army formed in the West Riding of Yorkshire just before the outbreak of World War II. Its service during the war included Home Defence during the Battle of Britain and The Blitz, and a length period in Middle East Forces. Postwar it continued to serve in the TA in the air defence role until 1955.
context_section_description: In June 1939, as the international situation worsened, a partial mobilisation of the TA was begun in a process known as 'couverture', whereby each AA unit did a month's tour of duty in rotation to man selected gun positions. On 22 August the whole of Anti-Aircraft Command was mobilised ahead of the declaration of war. The regiment deployed in the Humber Gun Zone as part of 39 AA Bde in 2 AA Division (although a new 7 AA Division was being formed to cover the area north of the Humber, its exact responsibilities had still to be worked out). RHQ was established at Paull Vicarage, and it drew its ammunition from the nearby Paull magazine. 221 (WR) Battery was at two sites on the south bank of the Humber, each with 4 x 3.7-inch guns, 270 Bty was at Paull, and 286 Bty at King George Dock, Hull, and at Brough. The regiment also temporarily deployed eight sections armed with Lewis guns to the radar station at Staxton-on-Wold in the light AA (LAA) role. (39 AA Brigade already referred to its AA gun regiments as HAA to distinguish them from the specialist LAA units that were being formed; this became official across the Royal Artillery on 1 June 1940.)
  On the outbreak of war, the Humber Gun Zone had 30 HAA guns, of which 28 were operational. These included 3-inch, 3.7-inch and 4.5-inch guns, but there was considerable shifting of guns between sites during the winter of 1939–40. On 23 September 1939, 91st HAA Rgt and the Humber Gun Zone were transferred to the command of 31 (North Midland) AA Bde in 7 AA Division but returned to 39 AA Bde and 2 AA Division in May 1940. In May, a composite battery drawn from 221 and 270 Btys was temporarily lent to 44 AA Bde to man a mobile 8-gun battery at Crewe.
  Additional guns began to arrive in the Humber zone, for example 286 HAA Bty took over eight newly-arrived 4.5-inch guns on three sites north of the Humber in May and 221 HAA Bty established a new 4 x 3.7-inch gunsite at Stallingborough in June. As of 11 July, the Humber Gun Zone had 38 operational HAA guns. In July, 286 HAA Bty moved to 2 AA Division HQ at Kimberley, Nottinghamshire, to become a divisional reserve battery and was replaced by 270 Bty back from Crewe. 286 Battery was soon deployed from Kimberley to man two semi-mobile 3-inch guns to defend RAF Horsham St Faith, with a section near Norwich. RHQ moved about this time to The Elms, Ulceby, North Lincolnshire.
caption: Static 3.7-inch gun preserved at Fort Paull.
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