In accordance with the Territorial and Reserve Forces Act 1907, which brought the Territorial Force into being, the TF was intended to be a home defence force for service during wartime and members could not be compelled to serve outside the country. However, on the outbreak of war on 4 August 1914, many members volunteered for Imperial Service. Therefore, TF units were split into 1st Line and 2nd Line units. 2nd Line units performed the home defence role, although in fact most of these were also posted abroad in due course.
1/1st Shropshire
The 1st Line battery was embodied with the Welsh Border Mounted Brigade on 4 August 1914 at the outbreak of the First World War and moved to East Anglia. It joined the 1st Mounted Division in September 1914, replacing 2nd South Midland Mounted Brigade which moved to 2nd Mounted Division. The battery was re-equipped with four 18-pounders on 30 December 1915 at Beccles. In March 1916, the Welsh Border Mounted Brigade was dismounted and left for Egypt. The brigade was replaced in the 1st Mounted Division by its 2nd line 2/1st Welsh Border Mounted Brigade and the battery remained with the division until August 1916. 2/IV London Brigade, RFA of 58th Division was broken up in July 1916 when it batteries were posted to 2/I and 2/II London Brigades, RFA . The brigade was reformed for 58th Division in August 1916 as CCXCIII Brigade, Royal Field Artillery with two gun batteries provided by 1/1st Shropshire RHA and 1/1st Glamorganshire RHA and two howitzer batteries and D. The Brigade Ammunition Column had been redundant since the Welsh Border Mounted Brigade had left, so the men were transferred to the 58th Divisional Trench Mortar Brigade. CCXCIII Brigade landed at Le Havre on 22 January 1917. On 6 February 1917, D Battery was split between D/CCXC Battery and D/CCXCI Battery; the remainder of the brigade became CCXCIII Army Field Artillery Brigade, RFA, now with two batteries of six 18-pounders and one of four 4.5" howitzers. At the Armistice, the battery was still with CCXCIII Army Brigade, RFA serving as Army Troops with the First Army.
2/1st Shropshire
Shropshire RHA formed a 2nd line in 1914, initially designated as the Shropshire Battery RHA and later given a fractional designation as 2/1st Shropshire Battery, RHA. The battery joined the 2nd line 2/1st Welsh Border Mounted Brigade on formation in September 1914. The brigade was posted to Northumberland in January 1915 and attached to the 63rd Division. In March 1916, the brigade joined the 1st Mounted Division to replace the 1st Line Welsh Border Mounted Brigade which was dismounted for service in Egypt. The battery joined CLVIII Brigade, RFA when it was reformed at Heytesbury, Wiltshire on 13 April 1917. The two RHA batteries provided the manpower for the Brigade Ammunition Column. At this point, the battery had been rearmed with 18-pounders. The brigade disembarked at Boulogne on 24 May 1917 and became an Army Field Brigade. On 6 July 1917, the battery was redesignated as A/CLVIII Battery and 2/1st Berkshire RHA became C/CLVIII Battery. At the Armistice, the battery was still with CLVIII Army Brigade, RFA serving as Army Troops with the Fifth Army.
Interwar
Shropshire RHA was reconstituted in the Territorial Force on 7 February 1920 when it formed a battery in 6th Medium Brigade, Royal Garrison Artillery and ceased to be a Royal Horse Artillery battery. The rest of the brigade was formed from the 6th Battalion, Cheshire Regiment and the Cheshire Brigade, RFA. The unit was later redesignated as 60th Medium Brigade, RA,. In January 1927, 240th Battery regained its sub-title as 240th Medium Battery, RA .
In 1938, 240th Battery transferred from the 60th Medium Regiment to 51st Medium Regiment, and fought with it throughout the Second World War, in 'Arkforce' during the Battle of France, in the Tunisian and Italian campaigns, and finally in Germany at the end of the war.
Postwar
51st Medium Rgt was placed in suspended animation in 1946. When it was reformed in the postwar TA as 351st Medium Rgt, the Shropshire RHA element instead joined 639th Heavy Regiment as P Battery, later becoming HQ RA of 48th District. In 1967, it became A Squadron in the Shropshire Yeomanry.