Shown here is a July 1940 line-up of Blenheim Mk.IV light bombers from Nos. 110 (VE), 15 (LS) and 82 (UX) Sqds showing the several distinct types of undernose turret installations fitted to the Blenheim Mk.IV: the standard installation featured a transparent perspex housing as seen on the third Blenheim from the camera. VE-A (R3741), nearest the camera, also features a fixed, remotely-controlled rear-firing 7.7 mm (0.303 in) MG in the topside of the port engine nacelle, this being a squadron 'lash-up'.
