Weight of Bombs dropped on the United Kingdom during 1939–45
All estimates are given in metric tons=2204.6 lbs. The term 'bombs covers high-explosive bombs, all mines, oil bombs and kilo incendiary bombs. Flying-bombs and long-range rockets have been estimated at one metric ton warhead.
It has to be emphasised that the figures given below are only estimates, and are not necessarily final. The difficulties of identifying every bomb dropped on land, and assessing its weight in metric tons, are sufficiently obvious without explanations of a technical character.
On 1st September 1941, a bomb census organisation, set by the Research and Experiments Department of the Ministry of Home Security, began to report the fall of bombs throughout the whole country. Previous to this date, the census operated in only certain selected areas. In the absence of comprehensive census returns, the only available bases for calculating the number and weight of bombs dropped are thee Air Ministry estimates of the number of long-range bomber sorties carried out by the German Air Force. Various assumptions were then made by the authorities concerning the average bomb load per day and night sortie for fighters and bombers, and tonnages were worked out accordingly.
Apart from the possibility of a wide range of error in estimating bomb loads, there was the difficulty of obtaining accurate data about the number of German planes in each sortie. Air Chief Marshal Sir Hugh Dowding described this problem in his despatch on the Battle of Britain.1 'Our estimates of the strength in which attacks were made is based on much less reliable evidence. The radio-location system could give only a very approximate estimate of numbers and was sometimes in error by three of four hundred percent. This is no reflection on the system, which was not designed or intended to be accurate in the estimation of considerable numbers; moreover, several stations were suffering from the effects of severe bombing attacks. As the average height of operations increased, the Observer Corps became less and less able to make accurate estimates of numbers, and, in fact, formations were quite often invisible from the ground.'
The claims made by the German Air Force in respect to tonnage considerably exceed the estimates shown in Tables 1 and 2. If the
difference between the claims put forward for seven heavy raids in 1940–12 and the Air Ministry calculations roughly measure the disparity, then it may be said that the German figure is 2·7 times higher than the British. This would mean, if the German claims were approximately true ,that 174,000 metric tons3—and not 64,993 (70,995 less flying-bombs and rockets)—.were dropped by piloted aircraft on the United Kingdom during 1939–45.
Estimated Tonnage of Bombs dropped on the United Kingdom 1939–45.4
Metric tons 1939 100 1940 34,870 1941 22,176 1942 3,032 1943 2,239 1944 1,963 1945 13 1944–5 (flying-bombs and rockets) 6,602 70,995
Estimated Tonnage of Bombs dropped on London civil defence region 1939–45.4
Metric tons 1940–1 8,200 1942 7 1943 142 1944 939 1944–5 (flying-bombs) 2,416 1944–5 (rockets 518 12,222
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1 Despatch submitted to the Secretary of State for Air on 20th August 1941 (supplement to The London Gazette, 10th September 1946).
2 London: 15th October and 15th November 1940, 19th March, 16th April and 19th April. Coventry: 14th November 1940. Birmingham: 19th November 1940.
3 Excluding flying-bombs, rockets and cross-channel shelling.
4 Source: Civil Defence Department of the Home Office.