The 99th (London Welsh) Heavy Anti-Aircraft Regiment, Royal Artillery was an air defence unit of Britain's Territorial Army (TA) during World War II.

The 99th Anti-Aircraft (AA) Regiment, Royal Artillery, was formed on 1 April 1939 as part of the expansion of the TA in the months leading up to the outbreak of war.

[1][2] In June 1939, as the international situation deteriorated, a partial mobilisation of Anti-Aircraft Command was begun in a process known as 'couverture', whereby each TA unit did a month's tour of duty in rotation to man selected AA positions.

On the night of 18/19 June the regiment fired its first shots against hostile aircraft, when single bombers over the GDA were illuminated by searchlights (S/Ls).

In August, while the Battle of Britain was progressing by day over Kent and Essex, Luftwaffe seaplanes regularly dropped parachute mines in the harbours and estuaries by night, which 29 AA Bde's guns and S/Ls attempted to counter.

[7][9] On 15 August Erprobungsgruppe 210 slipped through to attack RAF Martlesham Heath and got away without loss, despite being engaged by the Harwich AA guns while withdrawing.

[3][10][11] The number of HAA guns at Harwich dwindled from 15 on 21 August to 8 on 11 September as 6 AA Division redeployed them to guard the RAF's vital fighter airfields.

During November the battery moved around London, relieving gunners on different sites as the Luftwaffe continued to pound the city by night.

[3] Between 24/25 October and 2 January, the Italian Corpo Aereo Italiano made 10 raids (totalling 87 bomber sorties) against Harwich from its bases in occupied Belgium.

Afterwards it went to Norton Court near Bristol, and then to Headingley, Leeds, where the order for full mobilisation was received on 13 March 1943 and it came under War Office control.

By July it was part of 21st Army Group training for the Allied invasion of mainland Europe (Operation Overlord), in which it was designated a semi-mobile unit.

[21] After further training, at Larkhill on Salisbury Plain and at Tŷ Croes on Anglesey, the regiment moved to Southend-on-Sea in April 1944 to join 76 AA Bde under which it was to operate in 'Overlord'.

The remainder of the regiment's guns arrived the same day, and the REME workshop landed on 14 June amid shellfire and high waves that 'drowned' most of their vehicles, which had to be recovered.

The regiment was commended by XXX Corps for the accuracy of the airburst concentrations fired by B Trp in support of 49th (West Riding) Division.

If necessary, 99th (LW) HAA Rgt would come under that formation operating in the medium artillery and anti-tank (A/T) role supporting 11th Armoured Division and 3 AGRA.

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.

The intensity of this work increased on 8 February with the opening of First Canadian Army's offensive in the Reichswald (Operation Veritable) when the battery's 8 guns frequently fired over 1000 rounds per day.

[34][35][36] On 27 February the regiment (less 303 HAA Bty still operating the ground role) moved to Roosendaal to join the Antwerp 'X' defences, with four 4-gun sites constantly in action against V-1s and occasional Messerschmitt Me 262 reconnaissance jets during early March.

F ('Fox') Troop of 318 HAA Bty was detached to North Beveland where it operated as 'Tom Group' firing on ground targets in support of 4th Commando Brigade.

Although the South Scheldt defences were quiet, Tom Group was in daily action, suffering a few casualties from enemy Counter-battery fire.

On one occasion a gun was redeployed to engage a troublesome enemy OP in a tower; it fired 17 rounds, of which two hit the difficult target.

The brigade was ordered to cease fire on 3 May 1945 when a local truce came into effect to allow supplies to be sent to civilians in enemy-occupied Holland (Operation Manna).

[34][38] On 14 May the regiment was ordered to reorganise for garrison duties, and it handed in its guns and many of its vehicles, moving at the end of the month to Hamburg under 101 AA Bde where it took over responsibility for camps of Displaced Persons awaiting evacuation, and guarded Joachim von Ribbentrop, who had been arrested as a war criminal.

[2] General Sir Henry ap Rhys Pryce was Honorary Colonel of the regiment during World War II.