[9] By 1893 the War Office Mobilisation Scheme had allocated the 1st Hampshire Artillery Volunteers to the Portsmouth fixed defences.

The Hampshire RGA had the following organisation:[6][8][14][15][16][17][18][19] It was designated as a Defended Ports Unit in Southern Coast Defences, which was based at Portsmouth.

[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.

[29][30] 147th Siege Battery (see below) was formed at Portsmouth on 22 May 1916 based on a cadre of four officers and 78 other ranks from the Hampshire RGA (probably drawn in the main from 1/1st Heavy Bty, which disappeared from the order of battle by April 1917).

[29][31] A large number of other siege batteries were formed in the Portsmouth defences in 1915–16, which may also have included trained men from the Hampshire RGA among the recruits, although the Army Council Instructions did not specifically order this.

[33][34] After the beginning of air attacks on Britain the RGA also became responsible for manning anti-aircraft (AA) guns both at home and overseas.

[30][38] After serving in the Ypres Salient, the battery moved south in June 1916 to join Fourth Army in the opening bombardment for the Battle of the Somme, supporting the attack on Fricourt.

As part of 13th Heavy Artillery Group (HAG) it was positioned Marœuil near Arras firing in support of Canadian Corps.

The attack went in on 9 April, when the Canadians overran three trench lines and seized the crest of the ridge where the batteries soon established observation posts (OPs).

[30][38][40][41][42] At the end of the Arras Offensive the battery returned to Ypres, where it was brought up to a strength of six guns when it was joined by a section from the newly arrived 340th Siege Bty.

[29][30][38] Whereas batteries had previously been moved from one group to another, HAG allocations were becoming more fixed, and in December 1917 they were converted into permanent RGA brigades.

Later that month the battery was reorganised, a section from the newly arrived 446th Siege Bty joining on 22 September, bringing 147th up to a strength of six howitzers.

[29][30][44] On 16 December the battery was reduced to four guns once more, with a section leaving to help reform 190th Siege Bty, and joined 43rd HAG with Fourth Army the following day.

[29][30] 43rd Brigade RGA transferred from Fourth to Second Army on 1 May 1918 and remained with it until the Armistice, fighting through the Allied Hundred Days Offensive.

[44][43][53] For example, at the Fifth Battle of Ypres starting on 28 September, 43rd Bde's batteries directly supported the assault of 29th Division, having remained hidden and silent until Zero hour.

Such rapid progress could not be kept up, and German reinforcements halted further advances, but 29th Division had crossed the Ypres Ridge, the objective of so many failed assaults in 1917.

The TF was reorganised as the Territorial Army the following year, when the unit was redesignated the Hampshire Coast Brigade, RGA and the batteries were numbered 153–6.

[61] 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.

[64][70] By 1942 the threat from German attack had diminished, the coast defences were seen as absorbing excessive manpower and there was demand for trained gunners for the fighting fronts.

By this stage of the war many of the coast battery positions were manned by Home Guard detachments or were in the hands of care and maintenance parties.

[15][63][78][79][80][81][82] The coast artillery branch of the RA was abolished during 1956,[83] the regiment being officially disbanded on 15 September, but on 31 October it was instead converted to the Royal Engineers as 581 Construction Squadron, RE.