[8][9][10] With the Royal Navy's Home Fleet due to be based at Scapa Flow once more if war came, defences for the anchorage were an urgent requirement.

The Lord Lieutenant of Orkney and Shetland, Alfred Baikie, took the lead in raising batteries of anti-aircraft and coast artillery and fortress engineers in the islands.

The new unit manned the coast guns at Stanger Head, Flotta, Ness Battery and Stromness, and was supported by the Orkney Fortress Royal Engineers formed at the same time, which were responsible for the searchlights (S/Ls) and generators.

As a result, the Home Fleet left Scapa Flow until the booms and defences had been improved (including the Churchill Barriers).

They were stationed in remote locations on Orkney and Shetland, and during 1941 a programme of rotating batteries with other parts of the UK came into effect.

[35] The manpower requirements for the forthcoming Allied invasion of Normandy (Operation Overlord) led to further reductions in coast defences in April 1944.

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

By 1950 a decision had been made to equip some light semi-mobile batteries of coast artillery with the versatile 3.7-inch heavy anti-aircraft gun, which Q Bty trained to operate.

[40] When the coast artillery branch of the RA was abolished on 31 October 1956,[45] the regiment converted to the light anti-aircraft role and was reduced into 861 (Orkney & Zetland) Independent Light Anti-Aircraft Battery, RA, with its HQ and two Troops at Lerwick, one Troop and the pipe band on Orkney.

[40] Major Sir Basil Neven-Spence, Lord Lieutenant of Shetland, served as Honorary Colonel of 430 Regiment for several years.