The Carmarthenshire Fortress Royal Engineers (CFRE) was a coast defence unit of Britain's Territorial Army formed after World War I.

In World War II, it provided an anti-aircraft searchlight unit that served during the early part of The Blitz, and then during the Siege of Malta.

In 1935, HM Treasury approved expenditure on a new drill hall at Trimsaran for the company to share with a detachment of 4th Battalion Welch Regiment.

On 5 September, No 1 (EL&W) Co transferred a party of specialists to reinforce the Lancashire Fortress Royal Engineers at Walney Fort at Barrow-in-Furness.

The company settled into a routine of installing and operating electrical machinery at the twin forts as part of the fixed defences.

[12][14] The arrival in September of 1st S/L Rgt, which had been re-equipped since its evacuation from Dunkirk, allowed 45 AA Bde to complete the illuminated areas of South Wales.

On 28/29 September, 484 S/L Bty was moved to Plymouth, with BHQ at Bull Point Barracks, Devonport, where it came under 55th Light AA Bde.

Malta had been under air attack since the day Italy entered the war (11 June 1940) and urgently needed AA reinforcements.

[18][19][15][26][27][28] In February, the Luftwaffe 's Fliegerkorps X was ordered to neutralise Malta, and it began a series of heavy bombing raids, mainly at night, accompanied by mine-dropping in and around the harbour.

Increasingly, the Luftwaffe turned to Flak suppression, attacking the AA positions themselves with bombs and machine guns, and several S/L sites were hit.

By this stage of the siege, night bombers could be engaged by the HAA guns using visual height control at targets illuminated by S/L or by the GL Mark II gun-laying radar, or with predicted barrage fire.

Until December 1941, when Junkers Ju 88s began night operations, RAF Hawker Hurricanes were able to destroy 40 per cent of Italian-manned aircraft that had been illuminated.

[33][34] By October, the Luftwaffe had reinforced Fliegerkorps II, and a new round of heavy raids against the island began in an effort to restrict the RAF and Royal Navy's ability to interdict Axis convoys to Libya.

With the recent Axis defeat at Alamein and the Allied North Africa landings the same month, the siege of Malta was ended.

[35][36][37] In May 1943, Axis aircraft reappeared in an attempt to disrupt preparations for the Allied invasion of Sicily (Operation Husky), but these raids caused little damage.

[13][44][45] With the advances in radar technology, AA S/L units were under-employed by the end of World War II, but during the campaign in North West Europe 21st Army Group had pioneered the technique of reflecting light off the cloudbase to provide 'artificial moonlight' or 'movement light' (also known as 'Monty's moonlight' after 21st Army Group's commander, General Sir Bernard Montgomery) in support of night operations.