53rd (City of London) Heavy Anti-Aircraft Regiment, Royal Artillery was a volunteer air defence unit of Britain's Territorial Army from 1922 until 1961.

During World War II it fought in the Battle of France and The Blitz, and later served in India, where it was converted to Medium Artillery.

[1][2][3] One of the first officers appointed to the regiment was Robert Whittaker, a City banker who had seen service with the RGA during World War I.

In April 1940, a detachment of 3rd Searchlight Regiment RA was attached to SQUEAK II to evaluate RDF (early Radar) sets.

The regiment reached the Troyes area on the River Seine on 16 May and immediately sent parties back to recover the abandoned equipment – one such group being captured by the advancing Germans – and succeeded in retrieving all but six of its guns.

The advance party reached Salon-de-Provence, near Marseille on 9 June, joining HADDOCK FORCE, whose airfields were to support bombing raids by RAF Wellingtons against Italian targets.

[10] 158 Bty was evacuated with 12 AA Bde from St. Nazaire, and a party was on board HMT Lancastria when she was sunk with heavy loss of life on 17 June.

The ship put to sea on 18 June and slowly made its way to Gibraltar, where the AA gunners disembarked and temporarily reinforced the garrison.

On 27 June, 82 HAA Regiment arrived on the SS City of Cairo, and once they had been unloaded with their guns and equipment, 53 AA Rgt boarded the ship and sailed in convoy for the UK on 2 July.

[10][18][19] 53 HAA disembarked at Liverpool on 12 July and the men entrained for London, where the regiment came under the command of 49 AA Bde.

After various changes in location and command during the summer of 1940, the regiment moved to Rainham, Kent and joined 28 (Thames and Medway) AA Bde at the beginning of October, during the early stages of the London Blitz.

[24] In October 1941 the regiment was posted to Dover (where it experienced occasional German shelling) but at the end of the month prepared for deployment overseas once more.

[25][26][27] The Imperial Japanese Army Air Service began raiding Calcutta during the winter of 1942–43 and 53 HAA Regiment was involved in the defence of the city.

[38][39] Having fully trained on its new equipment, 85 Medium Regiment joined 59th Army Group Royal Artillery (AGRA) on 18 May 1945 with which it remained until the end of the war.

[26][34][35][37][39][40] In July 1945, 85 Med Regt formed an additional 'R' Battery from personnel who were not due for early demobilisation, and others transferred from 69 LAA Regiment which was returning to the UK.

[39] When the war ended, 59 AGRA was undergoing intensive training and waterproofing its vehicles for participation in Operation Zipper, a proposed landing by XXXIV Corps to liberate Malaya.