The German Thrust Eastwards Gives Further Respite for Strengthening the Home Defence Organisation
With the opening of the Balkan campaign by the German Command on the 9th April, culminating in a large expenditure of trained airborne troops for the capture of Crete, an invasion of England in the near future became less likely. The occupation of the Balkan peninsula was followed by the start of the offensive against Russia on the 22nd June.
By the end of July it was evident that the Germans were committed to a major campaign in Russia on a front of 1,500 miles with substantially the whole of their first line forces engaged, and all their supply and transport diverted to that front. After six weeks of fighting there was no sign of an immediate decision in favour of Germany; the Russians were still fighting hard, and German progress was in general being reduced.
From a military point of view, it was inconceivable that the Germans could break off the offensive until they had achieved a major objective either as a result of the capitulation of the Russian army in the field or by making such territorial gains as would preclude the possibility of further counter-action by the Russian forces.
The profound effect of continued Russian resistance on the war situation was outlined by the Chiefs of Staff on the 31st July. An invasion of the United Kingdom would be postponed; and the possibility of German adventures in Spain and North Africa would be reduced. While the security of the United Kingdom would necessarily remain the overriding consideration in our strategy, time would be given to send reinforcements, and particularly armoured fighting vehicles, overseas to strengthen our position in the Middle East the loss of which would be a military disaster of the first magnitude. In the North Atlantic much had been done to overcome the German attack and given more ships and aircraft for convoy protection and continued American assistance the Chiefs of Staff were confident that the threat to our trade and convoy routes could be mastered.
The Chiefs of Staff agreed with the opinion of the Joint Intelligence Committee that the Germans would be unable to disengage from the Russian front the large land and air forces required for an invasion of this country before the 1st September at the earliest. Calculating that 6 to 8 weeks would be needed to transport, re-equip, concentrate and embark them in the west, and to assemble the shipping and supply organisation, an invasion could not start before the middle or end of October, by which time winter would be setting in. The probability was that Russian resistance would extend the respite for the United Kingdom until the following spring (1942).
Appreciation by the C.-in-C. Home Forces
In view of the improbability of a decision on the Russian front in time for the German Command to mount an invasion against Great Britain before the winter the C.-in-C. Home Forces on the 1st August, wrote an Appreciation to determine the minimum requirement for Home Forces by the spring of 1942.
The appreciation is given as Appendix 22; and the following notes summarize the Home Defence plan for the spring of 1942 within its framework.