4th Home Counties Brigade, Royal Field Artillery

The 63rd Division was demobilised in early 1919 and CCXXIII Brigade went into suspended animation.[1][8] The unit was reformed on 7 February 1920 as a medium artillery brigade in the Royal Garrison Artillery (RGA), initially numbered 13th, but with the re-establishment of the TF as the Territorial Army in 1921, the unt was re-designated 52nd (Kent) Medium Brigade, RGA with the following composition:[1][2][9][10]

• HQ at Erith
• 205 (Chatham and Faversham) Medium Battery at Sittingbourne – formerly Home Counties (Kent) Heavy Battery, RGA
• 206 (Erith) Medium Battery (Howitzer) – formerly 4th Kent Battery
• 207 (Erith) Medium Battery (Howitzer) – formerly 5th Kent Battery
• 208 (Bromley) Medium Battery (Howitzer) at Penge – formerly Kent Cyclist Battalion[11][12]

On 1 Jun 1924 the RFA and RGA were subsumed into the Royal Artillery (RA).[9]

In 1935, the unit was one of a number of medium artillery units selected for conversion to the Anti-Aircraft (AA) role as 58th (Kent) Anti-Aircraft Brigade, RA, and was assigned to 28th (Thames and Medway) Anti-Aircraft Group of 1st Anti-Aircraft Division. In April the following year, 205 Battery was transferred to the smaller 55th (Kent) Anti-Aircraft Brigade, RA based at Rochester. When the TA was augmented at the time of the Munich Crisis, a new 264 Battery was raised on 1 October 1938 within 58th AA Bde at Dartford. On 1 January 1939 the RA redesignated its 'brigades' as 'regiment'.[1][2][13][14][15]

In May 1939 a new 6th AA Division was formed within Anti-Aircraft Command for the air defence of the Thames Estuary, Kent and Essex, and the 28th (Thames and Medway) AA Brigade and its units transferred to the new formation. 28th AA Bde was responsible for the 'Thames South' layout of gun sites. This organisation was in place when war broke out in September 1939.[16][17][18]

Opportunities for action were rare during the Phoney War, but on the night of 22/23 November 1939 the HAA guns of 28 AA Bde manning the 'Thames South' layout combined with those of 37 AA Bde on the other bank of the river ('Thames North') to engage at least two enemy mine-laying aircraft that had strayed into the mouth of the Estuary. One wrecked aircraft was found on the marshes and credited to 206 Bty of 58th HAA Rgt at Allhallows, Kent. [19]

On 1 June 1940, along with other AA units equipped with older 3-inch, newer 3.7-inch, or 4.5-inch AA guns, the 58th was designated a Heavy AA Regiment.[1][14]

The regiment was heavily engaged throughout the Battle of Britain defending the Medway Towns against German bombers.[20][21][22] On 18 August, for example, German air raids appeared over RAF airfields at West Malling, Manston, Kenley, Biggin Hill, Gravesend and the town of Sevenoaks, all within four and a half hours in the afternoon. All the gunsites of Thames South and its neighbours were in action and accounted for 23 enemy aircraft. Four days later a mass raid flew up the Thames Estuary to attack RAF Hornchurch on the Essex shore: the raid was broken up by the guns, and then the fighters of No. 11 Group RAF attacked. Follow-up raids were marked for the fighters by 'pointer' rounds of HAA fire. On 1 September over 200 aircraft attacked Maidstone, Biggin Hill, Kenley and Chatham: in joint action with the fighters, the guns broke up the formations and shot down four aircraft, but the airfields at Biggin Hill and Kenley were badly hit. Next day a mass raid arrived over the Medway and flew up the Thames towards Hornchurch. They came under heavy fire from the 3.7s and 4.5s and 15 were shot down before the fighters took over. On 7 September heavy raids up the estuary attacked oil wharves at Thameshaven, Tilbury Docks and Woolwich Arsenal: a total of 25 aircraft were destroyed by AA guns and fighters. On 15 September, remembered as the zenith of the battle, the guns were in prolonged combat, especially with aircraft over Chatham in the morning, and again in the afternoon.[23][24]

4.5-inch AA gun and crew of 207 Battery, 58th HAA Regiment, near Sittingbourne, Kent, January 1941

After 15 September the intensity of Luftwaffe day raids declined rapidly, and it began a prolonged night bombing campaign over London and industrial towns (The Blitz). This meant that the gunsites of 'Thames South' were in action night after night as the bomber streams approached the London Inner Artillery Zone (IAZ).[25][26] This period of intense activity lasted until May 1941, but occasional raids kept the AA defences on high alert.

On 12 July 1941 the experienced 206 (Erith) HAA Bty transferred to 60th (City of London) HAA Rgt. The regiment sent a cadre to 206th HAA Training Rgt, Arborfield, to provide the basis for a new 419 HAA Bty; this was formed on 10 April 1941 and joined the regiment on 7 July 1941 to replace 206 HAA Bty. The regiment later provided the cadre for 474 HAA Bty formed on 4 September 1941 at 207th HAA Training Rgt, Devizes, which joined 138th HAA Rgt.[14][27][28] In the autumn of 1941 the regiment left 28 AA Bde and joined 5 AA Bde in 9th AA Division covering South West England, while 419 Bty joined 474 HAA Bty at 138th HAA Rgt in 9th AA Division on 17 December 1941.[14][29][30]

By May 1942 the regiment had transferred again, to 44th AA Bde in 4th AA Division in Manchester. However, that month the regiment left AA Command and prepared to go overseas as a mobile unit.[30]

In September 1942, 58th (Kent) HAA Rgt joined First Army with the following composition:[31][32]

• 207 (Erith) HAA Bty
• 208 (Bromley) HAA Bty
• 264 (Dartford) HAA Bty
• 58 HAA Rgt Signal Section, Royal Corps of Signals
• 58 HAA Workshop Section, Royal Electrical and Mechanical Engineers
• 58 HAA Rgt Platoon, Royal Army Service Corps

3-inch AA guns on cruciform travelling carriages.

58th HAA Rgt was selected for the landings in North Africa in November 1942 (Operation Torch) with First Army.[1][20][21][33] Two batteries formed part of 22 AA Bde, regarded as the best trained in mobile operations and amphibious warfare. They were equipped with the older 3-inch 20 cwt gun on a modernised trailer, rather than the newer 3.7-inch. This was because the lighter 3-inch was easier and quicker to deploy in the rough country anticipated for the campaign. After sailing from the River Clyde they were landed on the coast of Algeria as infantry in the first flight of landing craft on 8 November, to be followed later by their heavy equipment. After the initial fighting, 22 AA Bde accompanied the leading elements of First Army on their long march eastwards, while 58th's batteries remained at Algiers to unload their guns and equipment and take up positions around the harbour and airfields. There was congestion at the docks, and AA guns had been given low priority in loading the supply ships, so the regiment could get only four guns into action by 10 November, eight more on the 11th, and four more on the 12th, during which time the port and airfields were under air attack. Follow-up elements of the regiment were lost when the liner Cathay was sunk on 11 November, and more men were lost in other convoys.[34]

Axis air command reacted quickly to the Allied invasion. As the AA troops moved into their positions they were dive-bombed in the open, particularly at Djidjelli airfield. One troop of 207th Bty and a troop of 45th LAA Rgt rapidly organised barrages in close defence, so effectively that three enemy aircraft were destroyed and the gun positions survived. There was a repeated attack, by Junkers Ju 87s and Ju 88s flying at 5000–6000 feet, on 22 November, which lasted two hours. The harbour at Bône became the most heavily attacked target in North Africa, and a troop of 58th HAA was sent to reinforce the AA defences there. On 21 November they fought raids by Ju88s, which set buildings and stores ablaze, and destroyed the AA units' small number of vehicles.[35]

During the next few weeks, AA defences for the Algiers area were built up into an integrated joint-service organisation, with the RAF installing early-warning radar and an operations room, and US Army AA Artillery units acquiring operational experience alongside British units.[36] As the build-up continued, 22 AA Bde could be released from commitments in the rear areas and assigned to airfield defence for No. 242 Group RAF. By January 1943, 58 HAA Rgt had a troop at Souk-el-Khemis Airfield, another at Souk-el-Arba Airfield and railhead, and a battery defending the port of Bougies under 52 AA Bde, while the third battery was supporting the advance of V Corps. Later the battery from Bougies was released and the airfield defences raised to a battery apiece by March.[37] In the final phase of the Tunisian Campaign (Operation Vulcan), 58 HAA came under 52 AA Bde as part of a mobile AA reserve ready to move up to Bizerta and Tunis immediately behind the battle groups. Some AA guns were deployed 'protecting' dummy armour assembly positions to deceive the enemy. As the Allies moved into Bizerta on 7 May the AA advance parties came under shellfire from the remaining enemy outside the town. The campaign ended on 12 May 1943, with 58th HAA Rgt claiming to have shot down 37 enemy aircraft during its course. Most of the AA units then settled down in defence and training for forthcoming operations.[38]

In the words of the Regimental Historian, 'One unit however, had only a short respite from new duties; 58th HAA Regiment, which had taken part in the original landing, was withdrawn from Bizerta, soon after it arrived there, to join a force for the invasion of Pantellaria'. An amphibious assault (Operation Corkscrew) on the Italian island lying between Tunisia and Sicily was accomplished on 11 June 1943. 207th HAA Battery embarked in landing craft on the night of 12/13 June, followed by its guns, 264th HAA Bty embarked on 14 June and RHQ and 208th Bty the following day. The batteries deployed and a regimental Gun Operations Room (GOR) was set up, fed by gun-laying GL radar sets. Enemy air attacks mounted from Sicily lasted for about two weeks after the invasion during which time 58th HAA fought a number of actions and brought down three enemy aircraft. 'The unit was then able to stand down and rest at its own island rest camp'.[39]

58th HAA Regiment was not involved in the invasion of Sicily (Operation Husky), but rejoined 22 AA Bde in mainland Italy in late October 1943 to take over the air defence of Naples. The defended area over the port, the anchorages and adjacent airfields was declared an Inner Artillery Zone (IAZ), giving AA guns priority over fighters at night. The problem of radar coverage of the Bay of Naples was partly solved when the new centimetric Mk. III GL radar became available. Luftwaffe raids over the city were frequent and heavy during November.[1][21][40][41]

The deployment at Naples turned into a long-term commitment. Heavy air raids resumed in March 1944, after which they progressively declined, and AA defence strength was also reduced, though 58th HAA Rgt remained there until the end of the war in Europe.[42] 58th HAA Rgt with 207, 208 and 264 HAA Btys was placed in suspended animation on 15 December 1945.[1][2][14]