143 Squadron has existed twice, once as a Home Defence fighter squadron in the later stages of WWI, and again as a Coastal Command Anti-Shipping Strike Squadron during WWII.
143 Squadron was first formed on 1st February 1918 as part of the 53rd (Home Defence) Wing, defending London against enemy bombers based in Belgium. For a month, the Squadron operated Armstrong-Whitworth FK8 two seat reconnaissance aircraft, changing to SE5a single-seat fighters from March to August 1918, and operating from Detling in Kent. They then re-equipped with Sopwith Camels, changing to Sopwith Snipes in June 1919. The Squadron was disbanded in October 1919.
The Squadron reformed on 15th June 1941 at Aldergrove as a long-range fighter unit of Coastal Command, equipped with Beaufighters. Up to December 1941, the Squadron operated from north-east England, and then Scotland, on convoy patrols along the East coast. In December 1941, 143 returned to Ireland, becoming a training unit operating Blenheims. In August 1942, the Squadron moved to East Anglia for convoy patrols and air-sea rescue missions, and in September began to re-equip with Beaufighters, becoming operational on anti-shipping raids in November.
The primary aim of these raids was to disrupt the flow of raw materials for the German war industry from Sweden to Germany, most significantly the supply of high-grade iron-ore. This was transported in heavily defended convoys down the Norwegian and Danish coasts to German ports, taking advantage of protection form fjords and off-shore islands wherever possible. Convoys consisted of small numbers of merchant ships defended by many more anti-aircraft ships and preceded by minesweepers. Initial operations showed the need to develop both weapons and tactics to be successful in sinking the merchant ships. Significant development of the torpedo was undertaken to permit successful launch from the Beaufighter, which launched torpedoes at much higher speeds than previous torpedo carriers (e.g. the Swordfish biplane). The structure was strengthened, and gyroscopically controlled tail fins added to control entry into the water, and a more effective explosive charge, Torpex, used. Tactics adopted included the adoption of the Strike Wing, with torpedo carrying aircraft being protected as much as possible by anti-flak aircraft attacking the flak ships, initially with cannon fire and bombs. Operating in shallow coastal waters, it was also necessary to drop torpedoes from sea to land, to minimise losses of torpedoes due to striking the sea bed. Also, as these operations were carried out close to the enemy-occupied coast, single-engined fighter escorts were essential to minimise losses from enemy land-based fighters.
Later, in 1943, three-inch rocket armament was introduced to the anti-flak squadrons, in two versions sharing the same solid propellant motor. The differences were in the warheads. The 25-lb. warhead was solid steel, armour-piercing, and the 60 lb. warhead a 6-inch diameter high explosive. It was found that the 60-lb. warhead was actually less effective, as the higher mass of the warhead resulted in greater deceleration and a much more curved trajectory after release, making accurate delivery much more difficult. Despite this, the 60 lb. rocket was initially used, superseded by the 25lb.rocket when it was realised that the greater accuracy overcame its theoretically lesser destructive power.
From 1942 to August 1943, 143 Squadron was an anti-flak unit of the Strike Wing based at North Coates in Norfolk, with 236 and 254 Squadrons. In August 1943, 143 Squadron moved to Cornwall to provide fighter support for anti-submarine aircraft operating over the Bay of Biscay, rejoining the Strike Wing in February 1944. In May 1944, 143 was moved to Manston to fly anti-E-boat patrols in support of the invasion.
de Havilland Mosquito FB-VI in 143 Squadron markings
In October 1944, 143 moved to Scotland to become part of the Banff Strike Wing, converting to Mosquitoes for attacks on enemy shipping off the Norwegian coast, continuing to operate in this role for the rest of WWII.
On 25th May 1945, the Squadron was disbanded and its personnel transferred to 14 Squadron.