In January 1891 the personnel from Portland were separated into the 2nd Dorsetshire AVC, but this was absorbed back into the 1st in June 1894, giving the following organisation:[5][6][8] By 1893 the War Office Mobilisation Scheme had allocated both Dorset Artillery Volunteer units to the Weymouth fixed defences.

When the divisional structure was abolished their titles were changed, the unit becoming the 1st Dorsetshire Royal Garrison Artillery (Volunteers) on 1 January 1902.

[27] By October 1914, the campaign on the Western Front was bogging down into Trench warfare and there was an urgent need for batteries of Siege artillery to be sent to France.

Equipped with two 12-inch howitzers on railway mountings it went out to the Western Front in December 1915 and served there for the rest of the war, latterly supporting First Army.

Slowly the British got the upper hand, and a large proportion of German guns were out of action when the infantry attacked on 31 July.

The Battles of the Menin Road, Polygon Wood and Broodseinde were highly successful because of the weight of artillery brought to bear on German positions.

[49][50] When the German spring offensive opened on 21 March 1918, 88th Bde was ordered to move to assist the hard-pressed VI Corps.

[39][52] 88th Brigade was still with VI Corps when Third Army joined in the Allied Hundred Days Offensive at the Battle of Albert on 23 August.

[58][59] By the beginning of November 88th Bde was standing by for further operations, but the enemy was retiring so rapidly that it was difficult to get heavy guns forward into range.

[30][60] It went out to the Western Front in October 1916, equipped with four 6-inch howitzers, and soon joined Fifth Army which was engaged in the final stages of the Somme Offensive.

[31][39] On 21 May 1917 174th Siege Bty was transferred to Second Army in the Ypres Salient where a mass of guns and howitzers had been assembled for the Battle of Messines.

Although this attack was characterised by the surprise explosion of 19 huge mines under the German lines at Zero hour, it was preceded by days of preliminary bombardment aimed at destroying strongpoints and the opposing artillery.

[31][38][65][66][67] After the Passchendaele fighting the battery joined 79th HAG, which became a permanent RGA brigade the following February; 174th Siege Bty remained with it until the Armistice.

[38] On 29 September IX Corps carried out an assault crossing of the St Quentin Canal, with 79th Bde amongst the mass of artillery supporting the operation.

[83] As the regimental historian relates, 'The guns of Fourth Army demonstrated, on 23 October, the crushing effect of well co-ordinated massed artillery.

When the TF was reconstituted as the Territorial Army (TA) in 1921, the unit was renamed the Dorsetshire Coast Brigade, RGA, and the batteries were numbered 179 and 180.

The guns were controlled by Portland Fire Command at Weymouth and companies of the Dorsetshire Fortress Royal Engineers manned searchlights for coast and anti-aircraft defence.

[91] With the danger of invasion after the British Expeditionary Force was evacuated from Dunkirk, the coastal artillery regiments underwent a major reorganisation in the summer of 1940.

On 1 July the Dorsetshire Heavy Regiment was redesignated 522nd (Dorsetshire) Coast Regiment and reorganised as six batteries, designated A to F.[18][88][92][93][94] A number of emergency batteries of ex-Royal Navy guns were obtained for the South Coast ports, including two 6-inch Mk XII naval guns manned by the army, ordered for Poole Harbour on 22 May.

[92][96] On 1 April 1941, A to F Btys were numbered 102 to 107, and on 10 May 1941, 239 Independent Coast Bty (formed on 10 March) was attached to the regiment for administration and training, stationed at West Bay, Bridport Harbour, with 2 × 5.5-inch guns and 2 × searchlights.

[93][102] As the invasion threat receded, the coast defences were seen as absorbing excessive manpower and were scaled back, the gunners being redeployed.

569th Coast Rgt had been disbanded in early 1943, and its batteries rejoined 522nd, giving the following organisation:[92][96][102][105] However, Portland Harbour was a major concentration point for shipping being assembled for the Allied invasion of Normandy (Operation Overlord), and Weymouth Bay was used for invasion exercises, so 522nd Coast Rgt did not see the same reductions as regiments elsewhere.

Nevertheless, by the end of 1944 serious naval attacks on the coast could be discounted and the War Office began reorganising surplus coastal units into infantry battalions for duties in the rear areas.

[114][115][116][117][118] The 5th and 6th Dorsetshire AVCs wore distinctive buttons marked with a crown above a field gun and a laurel spray on either side.