"Viribus vincimus" (By strength we conquer).
A hand erased at the wrist, holding a dumb-bell. The dumb-bell was used as a badge by the squadron in 1917 and symbolises strength.
HM King George VI, July 1938.
History of 21 Squadron:
No. 21 Squadron, RFC, was formed at Netheravon, Wiltshire, on 23rd July 1915, and went to France in January 1916, as a general duties squadron equipped with RE7 aircraft; it was, incidentally, the only unit to serve overseas equipped with RE7s throughout. The squadron's initial duties were mainly strategic reconnaissance and patrol but from 9th March it was also employed on bombing. On 30th June 1918, on the eve of the great Somme offensive, six of its RE7s opened the RFC's bombing programme by attacking the railway station at St. Sauveur, near Lille, where the enemy was known to have been stockpiling ammunition. Each RE7 carried a 336-lb. bomb and this was the first occasion on which the big, heavy-cased Royal Aircraft Factory bomb was used in France.
In August 1916, the squadron was re-equipped with the BE12 single-seater and during the next 5 to 6 months was engaged on offensive arid defensive patrols, escort work, and bombing. In February/March 1917, it was re-equipped with the RE8 and assumed the duties of a corps squadron. It remained in this role for the remainder of the war and for its work during the Messines offensive in the spring of 1917 was congratulated by General Trenchard in person who said it was the best artillery squadron in France.
Disbanded in October 1919, No. 21 was re-formed as a bomber squadron at Bircham Newton in December 1935, and equipped with the Hawker Hind two-seat day bomber. It later moved to Abbotsinch, Lympne and Eastchurch, and on the outbreak of war was based at Watton, Norfolk.
During the early part of the war, No. 21 Squadron, flying Blenheim IVs, played a prominent part in No. 2 Group's offensive against shipping in the English Channel and the North Sea, and "fringe" targets on the Continent. The squadron went to Malta in December 1941, and, flying from Luqa, attacked shipping in the Mediterranean and land targets in North Africa. It was disbanded on 14th March 1942, and re-formed the same day in England. Later that year it received new equipment in the form of the Lockheed Ventura, and on 6th December, operating from Methwold, was one of the squadrons which made the daring low-level attack on the Phillips radio and valve factory at Eindhoven.
No. 21 continued daylight operations with Venturas-albeit spasmodically - until early September 1943, and soon afterwards began to convert to the fighter-bomber version of the de Havilland Mosquito. During the remainder of the war it was mainly employed on night bombing, but also took part in several special daylight precision attacks, including such spectacular ones as those against the Gestapo Headquarters at Aarhus in Denmark on 31st October 1944, and the Gestapo Headquarters at Copenhagen on 21st March 1945. In February 1945 the Squadron moved to France and carried out intruder raids over Germany for the rest of the war and was disbanded on November 1947.
One of No. 21's Mosquitos, LR385 "D-Dog", made 104 operational sorties (on 91 of which bombs were dropped) with the squadron. It flew its first op on 6th February 1944, when it bombed a V-weapon site at Bois Coquerie, and its 104th op on 29/30th November 1944, when it bombed a railway - including a train - and also strafed a factory during a patrol immediately behind the battle line.
On 21 September 1953, No. 21 reformed at Scampton as part of the home-based Canberra force, disbanding on 30 June 1957. On 1 October 1958, No. 542 Squadron at Upwood was renumbered No. 21 Squadron. Most of the Squadron was sent to Laverton, Australia in connection with nuclear weapons trials until the beginning of 1959 but the Squadron was again disbanded on 15 January 1959. On 1 May 1959 No. 21 was reformed at Benson as the first Twin Pioneer Squadron moving to Kenya in September. The Squadron then moved on to Aden in June 1965 until it was disbanded on again 15 September 1967. On 3 February 1969 the Western Communications Squadron at Andover was renamed No. 21 until it was disbanded on 31 March 1979.