Did they actually make such a Dud in such numbers????? --Defiants__
" The innovative but heavy Boulton-Paul Defiant was withdrawn from daylight operations following the tragedy of 141 Squadron on 19 July 1940, when six out of its nine Defiants were shot down in fighter-vs-fighter combat. Dowding was very well aware about combat experiences with this aircraft and supported the decision of its removal from first-line strength."
--" The Defiant, after some striking initial successes, proved to be too expensive in use against fighters and was relegated to night work and to the attack of unescorted bombers. It had two serious disabilities; firstly, the brain flying the aeroplane was not the brain firing the guns: the guns could not fire within 16 degrees of the line of flight of the aeroplane and the gunner was distracted from his task by having to direct the pilot through the communication set. Secondly, the guns could not be fired below the horizontal, and it was therefore necessary to keep below the enemy. When beset by superior numbers of fighters the best course to pursue was to form a descending spiral, so that one or more Defiants should always be in a position to bring effective fire to bear. Such tactics were, however, essentially defensive, and the formation sometimes got broken up before they could be adopted. In practice, the Defiants suffered such heavy losses that it was necessary to relegate them to night fighting, or to the attack of unescorted bombers.

Read somewhere that "night fighters" were mostly a name, at night at this stage of the war most were just flying blindly and hardly ever saw or shot a target....