when 134 bombers carried out what would later be described as an 'area bombing' raid on Mannheim as retaliation for recent German bombing.
Air Marshal Peirse had just cause to resist some of the demands made upon his force; Bomber Command was losing rather than gaining strength. When Peirse took over in October, the theoretical strength of the operational squadrons had doubled since the outbreak of the war. The daily return to the Air Ministry's War Room now showed a strength of 532 aircraft - 217 Blenheims, 100 Wellingtons, 71 Hampdens, 59 Whitleys and 85 Battles. There was much difficulty in finding a useful role for the large force of Blenheims now that the invasion threat had passed and the Battles, which had come back from France, were obsolete and would fly their last operation on the night of 15/16 October. In the five months to be covered by this coming period of the diary, the Blenheim strength would fall to 150 aircraft, which could only be used in limited roles, and the Battles would depart completely. The Whitleys and Hampdens, both due for replacement by more modern types of aircraft, did no more than hold their own in numbers but the sturdy and reliable Wellingtons would almost double their strength, mainly in the establishment of 1 Group as a regular night-bombing force with this type. Operations under the new commander-in-chief thus commenced with a force of only 230 aircraft of types suitable for night operations in winter, of which a proportion were always manned by inexperienced crews or were suffering from servicing problems. Peirse's realistic maximum strength for night operations was no more than 150 aircraft.
So the pattern of raids continued, with a greater emphasis on Germany but with a significant slackening of numbers dispatched. Most of the operations were by night, with small numbers of aircraft sent to many targets still being the normal routine. But the new commander does seem to have selected the best moonlit night in each month and gathered his strength of aircraft for a concentration of effort on one German city. In this way, Hamburg was attacked by 130 aircraft in the middle of November and Mannheim and Gelsenkirchen by similar numbers in December and January. The relaxation of pressure did allow for the less experienced crews to be introduced to operations more gradually; these 'freshman crews' were usually sent to a relatively safe target on the coast of one of the occupied countries until judged ready to tackle more distant targets.
The employment of the 2 Group Blenheims continued to pose major problems. At least four squadrons left for conversion to Wellingtons with other groups but those squadrons which remained saw little action. A small proportion of the strength available continued to be used on night raids but daylight operations brought little satisfaction. In January 1941, a new type of Blenheim operation was introduced, the Circus. In this, a handful of Blenheim bombers was dispatched with a large escort of the R.A.F. day fighters now available in Britain and, like the Blenheims, freed from the threat of invasion. The targets attacked by the Blenheims were rarely of importance but the true purpose of these operations was to draw the Luftwaffe fighters into action. The British fighters would then join combat and, in this way, it was hoped, a successful war of attrition against the Luftwaffe could be waged. The whole concept was hampered by the limited range of R.A.F. fighters and only a small area of northwest France around the Pas de Calais and parts of Belgium could be reached. The Luftwaffe could join battle or decline to do so as it wished. Some thought it a poor employment of resources but the alternative was to keep unemployed the large forces of day bombers and fighters which might one day be needed to defend Britain from invasion if the Germans did resurrect their plans and whose successors would certainly be needed on that dimly distant day when Allied forces could re-invade Europe.
Night-bombing operations proceeded steadily in October and November, though with many more aircraft than before turning back or failing to find their designated primary targets for weather reasons. With midwinter came a definite reduction in the scale of operations and this period really just fizzled out on the quietest of notes in January and early February. The general level of operations during the whole period was less than half that of any time since the German invasion of France and the Low Countries in May 1940.
