Difficult to phrase this question right but, to elaborate, how did Britain expect to defeat Nazi Germany before the US & Soviet Union entered the war? Was there an assumption that they would have to continue fighting alone, and if so how did they propose to do this? Was a Britain-only D-Day conceived for example?
This is something I’ve been thinking about recently but have been having a hard time researching. I appreciate that much of 1940 would have been focused on fighting the Battle of France, then the immediate concern was short-term planning to win the Battle of Britain. However there must also have been a long-term view about how to prosecute the war, especially in late 1940/early 1941 when it was clear that Britain was no longer under threat of invasion and could free up resources from home defence.
I have a sneaking feeling that the answer is going to be, simply, buy time until the US & USSR do get involved. If that is the case, how certain was Churchill et al that this would happen? Obviously the US was doing all but actually fighting at this point (and even then in the Atlantic), and Nazi rhetoric certainly supported a war with the USSR, but were there any guarantee or was Britain gearing up to “go it alone”?
First, it is crucial to understand Britain's strategy before the fall of France. Natural geography would allow the U-Boat threat to be somewhat contained in the North sea through sealing the straights of Dover and active patrolling and mining of the north sea in a line from the Orkneys and Shetlands to Norway. This would additionally blockade German ports, protect British shipping lanes, and allow for the build-up of empire and dominion forces in Britain prior to their deployment in France. The RAF would emphasis interceptor fighters to protect British cities, with a strong strategic bombers and a measure of coastal patrol aircraft to attack German industry and aid the Royal Navy’s efforts. Consequently there was little initial focus upon tactical air support or naval aviation to British strategic at this time, while the under-equipping of costal command would later have serious problems during the battle of the atlantic.
These measures would allow for a significant portion of Britain's manpower to be deployed into the army. During the 20s and 30s, fierce spending cuts had caused severe economies in army funding, however this was balanced by domestic, political and military desires to create a material orientated army to avoid the bloodshed of the western front. Its weaponry- cruiser tanks, Bren guns, Bren carriers, 2 inch mortars and 25 pounder guns, prized mobility over firepower, while economising on manpower. The proposed large inter-war army (of some 60-70 divisions) would mirror this, but would demand significant combat and service support, and would take significant time to be armed, trained and deployed, reflecting the British appreciation that military effectiveness lay in proficiency across the board of military activities, rather than their opponent’s narrow emphasis upon combat and maneuvre. The BEF of territorials and regulars, in combination with their French allies would hold out until this massive force was properly prepared for combat. This army would consequently arrive once French and German manpower reserves had been exhausted, allowing them to secure victory and a position in the world where Britain could exercise considerable post-war influence.
The fall of France however changed all of this. Instead of the French army bearing the brunt of the 400 division strong German army, Britain would have to face this behemoth alone. German U-boats, operating from Atlantic and Mediterranean ports would be able to attack British shipping over far greater areas of water, while British Cities would face the undivided attention of the Luftwaffe.
Consequently the RAF, the Royal Navy and the Merchant Marine received the lion's share of Britain's manpower reserves, as they represented the best means of ensuring Britain's continued survival, while striking at the Germans. The Navy and Merchant marine demanded considerable resources so as to hunt the U-Boat threat and maintain its numbers in the face of considerable losses. The RAF would defend British cities while a massively expanded bomber command represented a means to strike at their enemy.
The battered British army, withdrawn from Dunkirk, was to become the nucleus of a much smaller force- 35 divisions total. This was partially offset by a production run of equipment and weaponry sufficient to arming a total of 55 divisions, providing material for resistance groups and the arming in Britain of free French, Norwegian, Dutch Belgian and other formations. This low number of field force formations would additionally be offset by a focus upon material to maximise the individual strengths of these divisions, Britain ultimately raising one armoured division (or independent armoured brigade) for every 2.5 infantry divisions, a far higher figure than that of the United states (one to 3.5) or the German army (one to 8.5). Infantry divisions were also very large by contemporary standards and complete mechanised, deploying some 18,000 men with 4,000 vehicles, in comparison to their German opponents who usually fielded divisions of 12,000-15,000 men with 700 vehicles and some 4,000-5,000 horses. The these division would be supported by massed artillery units (AGRAs) or Royal Engineer formations (AGREs) in addition to a number of specialised combat service support units. In short the emphasis was upon a small, but well rounded force stemming from a more holistic visions of war as the sum of combat, combat support and combat service support activities to overcome their opponents superior number of field able divisions which stemmed from their narrower focus upon combat arms.
The overall strategy was consequently long-term and initially indirect in its approach. The resistance groups, in combination with rapid amphibious and airborne assaults and a variety of unconventional forces (commandos, paras, SAS, SOE operatives) would disperse German forces in counter-insurgency operations, maintaining allied morale and growing capability in joint operations, while enemy forces suffered from constant, attritional attacks. When the enemy was finally severely weakened from naval blockade, air attack and continuous guerrilla action over years of war, the well prepared and massed British empire forces would be finally deployed in a massive invasion and decisively defeat the enemy. in 1940 this was tentatively pencilled as some time in 1942-3 but given the entry of japan into the war and any number of other factors this timeline was hopeless optimistic and I have not seen any concrete realistic dates offered.
The entry of the USSR and the USA brought with it a more concrete focus upon the when's and whereas of continental invasion (as planning had previously been vague, under-resourced and more focused upon developing capability), as well as bringing with it a more concrete date for continental invasion in the 1943-44 period after a series of political conferences bound the British empire and its dominions to that date. It is however important to note that this strategy was to a certain extend developed in isolation from these two powers as it was felt that war between the USSR was an unreliable and unlikely ally given their attack upon Finland, their purges and actions in Poland. Furthermore war between the USSR and Germany was highly unlikely, and while the US entry into the war was highly desirable, it was not possible to base their strategy upon it.
To conclude, Britain's strategy was balanced between winning and surviving the war, and their updated plan can be characterised as an modernised version of their Napoleonic war strategy. Carrying out maritime economic warfare again a land-bound adversary, formenting revolution in occupied nations and rapid amphibious raiding would disperse and demoralise superior enemy numbers, while preserving and gathering British strength until the enemy was so weakened that Britain's comparatively numerically limited (but well prepared) ground forces could be deployed for a knock-out blow.
Sources
P.G. Griffith ‘British Armoured warfare in the western desert 1940-43’ In Harris, J.P., and Toase F.N. Eds., Armoured Warfare (Ellesmere Port, Deltatype Ltd., 1990)
Bidwell S., and Graham, D., Fire-Power (Barnsley, Pen and Sword Books Ltd., 2004)
Buckley, J., British Armour in the Normandy Campaign (London, Frank Cass, 2006)
Buckley, J., Monty’s Men (London, Yale University Press, 2013)
English, J. A., and Gudmundsson, B. I., On Infantry, (Westport, Greenwood Publishing Group Inc., 1994)
French, D., Raising Churchill’s Army (Oxford, Oxford University Press, 2000)
Hart, S.A., Colossal Cracks (Mechanicsburg, Stackpole Books., 2007)
Keegan, J., Six Armies in Normandy, (London, Pimlico, 2004)
Place, T.H., Military Training in the British Army, 1940-44 (Abingdon, Routledge, 2000)
As far as I can tell, there was not much about that sort of thinking going on. The strategy that they had all depended on fell apart and nobody that I have read really had a really well thought out Britain alone global strategy that was very different innovative. For the British Napoleonic Wars were still the default reference of thinking.
Britain Strategy consisted of defending the home island, keeping control of the sea, containing the expansion of the Axis and seeking local allies to do the fighting for them if possible.
From this it followed two very important policy choices, blocking the Italians expansion in Africa and possible a German attack threw Turkey. For that reason even while the Battle of Britain was raging, many good troupes were deployed to the middle-east command. As long as Russia stands, this gives security to the much of the British Empire and contains the Axis in Europe.
Once Russia and the Germany started fighting, the British were very quick in delivering significant amounts of goods to the Russia. I have read multiple generals saying that the survival, if not victory, of the soviet union is vital for Britain. They even sent vital troupes and supplies for the defense of Singapore to Russia instead. Together with the maritime strategy and the middle-east position this contains Germany in a resource poor place, blockade is always the default assumption for the Brits.
There were ideas around to build a Balkan front consisting of a Turkey, Greece, Yugoslavia and a large supplement of British troupes to open a Southern Front against Italy and then Germany. This eventually manifested itself in the horribly failed Greece expedition. Even once that had failed, recurring Turkey to the allies was a long standing plan and worked on thought out the war.
The US only changed the picture in terms of numbers and resources, the strategy remained much the same (at least if we don't look at Japan, that a hole other discussion). Containment with hopefully an eventual dagger thrust threw the Northern Plains.
Some resources:
This contains much of the development of Alanbrooke strategic ideas and choices. He was the primer strategist of the allies.
This is a good book because Wavell was a well known General during that time and he had a huge strategic command. It contains some discussion about the first reactions to the fall of France and how that changed Wavell thinking about his position in the middle-east.