Churchill circulated a memorandum to the War Cabinet detailing the impact of enemy sinkings of merchant shipping. It was part of the analysis that he was giving to Harry Hopkins to take back to the United States to discuss with President Roosevelt. The U-boats were having particular success during this period as the Royal Navy struggled to develop the technology and the capacity to counter them.
Since the outbreak of war we have lost about 2 million gross tons more shipping than we have built or captured. This has been approximately made good by bringing home British ships normally trading abroad and by buying and chartering Allied and neutral ships, which now work for us full-time instead of part-time as formerly. Thus the total shipping effectively at our disposal is about the same as in peace time.
Formerly nearly half our imports came from European countries and the north coast of Africa. These sources no longer being available, and the Mediterranean being practically closed to merchant shipping, we are forced to import from more distant sources and the average haul is increased by about half. In addition, the time of turnaround in port has been increased by blackout and other war time difficulties and by the concentration of unloading in the Western ports. These two causes together with convoy delays make the average round voyage last about one and a half times as long as formerly. Hence if nothing else intervened we should be able to import some two thirds of the normal amount.
In addition, however, it has been necessary to divert about one sixth of our importing capacity to the fighting services, a factor which has been increased by the campaign in the Middle East. Thus it seems likely that we shall not be able to import even two thirds of the normal amount. Indeed, if sinkings continue at their present level our merchant fleet, which has been maintained largely by windfalls in the shape of French, Norwegian, Danish ships, etc will diminish and our importing capacity will be even further reduced. This would gravely imperil our war effort.
He then went on to consider particular requirements, including ‘Food':
It is reckoned that the minimum food import required to maintain efficiency is about 16 million tons, 70 per cent, of the 23 million tons imported before the war. This involves cutting animal feeding-stuffs by about 4 million tons, which will reduce our stock of meat on the hoof, the safest kind of stock in case of air attacks.
It will, of course, also reduce our supplies of bacon, eggs and dairy produce, already greatly depleted by the collapse of the Continent, but every effort is being made to maintain the children’s milk supply which depends upon imported oil cake. It also implies increased imports of fertilisers essential to augment our home food production.
We plan to reduce fruit and vegetable imports from two and a half million to half a million tons, and to cut one million tons of other foods, such as sugar, meat, butter, eggs, etc
The consumption per head in December compared with pre war rates is shown below for a few food-stuffs :—
Butter 29% of pre-war.
All fats 81%
Bacon and ham 82%
Other meat 86%
It is evident that we cannot cut much further without reducing the stamina and morale of the people.
See TNA CAB 66/14/39