The Honourable Artillery Company (HAC) of London is the senior regiment of the British Army's Reserve Forces, with a history dating back to 1537.

[10] The original personnel of the regiment and its recruits were of high quality and many of the other ranks (ORs) were selected for officer training (over 800 by September 1940, and 1178 by the end of the war).

RHQ moved to Bush Hill Park Golf Club at Enfield in May and Lieutenant-Colonel Basil Trappes-Lomax, MC, took command of the regiment.

[10][13][14] During the summer of 1940 the Battle of Britain was raging over Southern England, and 273 Bty fired the regiment's first shots at a hostile aircraft on 22 August.

In November, 86th (HAC) sent another cadre to 206th HAA Training Regt at Arborfield, where it was joined by an intake of soldiers from 225 and 233 LAA Troops, which had been formed in August 1939 for airfield defence and were now being disbanded.

[1] On 3 January 1942, the regiment was placed on the Army Troops Reserve Roster, indicating that while remaining in AA Command it would begin training for a future mobile role in the field force.

[1][20][22] On 1 December 1942, 86th (HAC) HAA Rgt was formally transferred from AA Command to Home Forces, and moved to Mushroom Farm Camp, Wethersfield, Essex.

[20][23] Until February its batteries were loaned out to AA Command Gun Defence Areas (GDAs) at Norwich, Lincoln and York, which had been established during the Baedeker Blitz the previous year.

[24][25] By now, the regiment consisted of RHQ and 273, 274 and 383 HAA Batteries, each equipped with 8 towed 3.7-inch guns in two troops of 4, with Gun-Laying (GL) radar.

Light AA defence was emphasised at the start of the operation, since low-level attack by Luftwaffe aircraft was considered the most likely threat.

However, 86th HAA Rgt was one of the designated assault regiments to land on D-Day with minimum scales of equipment, to be brought up to strength by parties arriving later.

The assault group included elements of 73rd and 114th LAA Rgts equipped with towed and self-propelled (SP) 40 mm Bofors guns, and a troop of 93rd LAA Rgt equipped with the new 20 mm Polsten gun in triple mountings, half towed and half mounted on Crusader tank chassis.

[5][29][35] As the build-up in the Normandy beachhead grew during June and July 1944, 80th AA Bde was tasked with protecting Juno and Sword beaches, the small port of Ouistreham, and the Orne and Caen Canal bridges.

During August, the regiment regularly lent troops of 3.7-inch guns for ground firing near Caen, for example during the closing of the Falaise Pocket.

[5][29][37] When 21st Army Group finally broke out of the Normandy beachhead in August 1944, 86th (HAC) was at first left providing AA cover for the beaches, for Caen and the Canal.

But, on 6 September, it moved forwards, 274 Bty to provide AA cover for the river crossings at Rouen, the rest of the regiment in the ground role to support the capture of Le Havre (Operation Astonia).

The regiment fired some 1700 rounds, directed by its own Observation Post (OP) across the Seine estuary in the suburb of Honfleur, initially to suppress German Flak positions before the port was bombed by the Royal Air Force.

Afterwards, the regiment moved up to provide AA defence at Dieppe after its capture, with E Troop of 383 Bty in a coastal artillery role.

[5][29][30][39] A short history of the regiment in the War Diary notes the irony of the Honourable Artillery Company of London defending that city's historical trade rival.

In mid-November, the regiment completed its radar training and moved to the Brussels 'X' defences under the operational control of 101st AA Bde, commanded by Brigadier John Ross, the 86th (HAC)'s former CO.

Despite concerted attacks on nearby airfields by Luftwaffe fighters on 1 January (Operation Bodenplatte), the ground situation was well under control and the AGRA and local defence plans were cancelled on that day.

With the new equipment the regiment's success rate climbed to over 50 per cent of the targets engaged, but falling V-1s also presented dangers: one was shot down and fell into C Troop's 'Wagon Lines', killing one man and injuring three others, as well as destroying 10 vehicles.

[45][46] In late April 1945, the regiment was stationed on the islands of Walcheren and South Beveland, protecting the approaches to the port of Antwerp in both AA and coast defence roles.

When Walking Out Dress was worn (probably only after World War II), all ranks wore HAC pattern buttons and shoulder chains.