Flying in its characteristic nose-down attitude, Armstrong Whitworth Whitley V Z6640 of No 78 Sqn displays 29 completed-sortie bomb symbols. On the outbreak of war No 78 Sqn was designated a reserve unit for training crews, but the formation of dedicated OTUs in 1940 saw it shifted to night bombing sorties over Germany.

The first Bomber Command unit to be established as part of Article XV was No 405 Sqn RCAF, formed in April 1941 at Driffield with Wellington IIs, the latter being replaced with Halifaxes in April 1942. The centre Halifax B.II Series 1 (Special) seen here is W1173, LQ-X, of No 405 Sqn. Note the maple leaf insignia beneath the cockpit.

Built by Vickers at Hawarden, Wellington IV Z1392, bearing the unit code “UV” and the individual letter “G”, is depicted here in the colours it wore while serving with No 460 Sqn RAAF (motto "Strike and Return”) in the spring of 1942.

A rare photograph of a Wellington IC of “E” Flight, No 21 Operational Training Unit (OTU), based at Moreton-in-Marsh in Gloucestershire. After commencing flying operations in the spring of 1941, No 21 OTU was tasked specifically with training crews for the Middle East. Note No 21 OTU’s “SJ” code letters on the fuselage.

Heads up! A Wellington I of No 11 OTU performs a lively low-level pass over the grass at the unit’s base at Bassingbourn in Cambridgeshire. One of the RAF’s newer bases, Bassingbourn opened in March 1938 and was the most easterly of Bomber Command’s OTUs, and was thus subject to frequent attacks from Luftwaffe intruders.