The 76th Searchlight Regiment, Royal Artillery (76th S/L Rgt) was a British Army air defence unit during World War II.

It was engaged during the Battle of Britain and The Blitz, defending Royal Air Force airfields and the towns of southern England.

The cluster system was an attempt to improve the chances of picking up enemy bombers and keeping them illuminated for engagement by AA guns or Night fighters.

485th and 493rd Btys received their first Gun-Laying Radar Mk I sets in December and became operational at the end of the year.

It was also engaged in experiments at RAF Boscombe Down to see how searchlights combined with AA guns could deal with low-flying attacks.

[18] On 20 February 1943, 474th S/L Bty ceased to be part of 76th S/L Rgt and became an independent unit training for a mobile role in Operation Overlord, the planned invasion of continental Europe.

[18][20][21] As the threat from the Luftwaffe waned after D Day, the War Office warned in June 1944 that AA Command would have to release manpower to provide reinforcements to 21st Army Group fighting in North West Europe.

[22] The run-down began in the autumn: RHQ of 76th S/L Rgt with 485, 492 and 493 S/L Btys commenced disbandment at Woolacombe, North Devon, on 23 September 1944, completing the process on 3 March 1945.