In December 1940 Churchill considered the question of Ireland.
'As November and December drew on, the entrances and estuaries of the Mersey and the Clyde far surpassed in mortal significance all other factors in the war. We could of course at this time have descended upon de Valera's Ireland and regained the southern ports by force of modern arms. I had always declared that nothing but self-preservation would lead me to this. But perhaps the case of self-preservation might come. Then so be it'
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In fact the only action which Churchill took was to stop subsidies
Prime Minister to the Chancellor of the Exchequer 01/12/1940
'The straits to which we are being reduced by Irish action compel a reconsideration of the subsidies to Ireland. It can hardly be argued that we can go on paying them till our last gasp. Surely we ought to use this money to build more ships or buy more from the United States in view of the heavy sinkings.
Pray let me know how these subsidies could be terminated, and what retaliatory measures could be taken in the financial sphere by the Irish, observing that we are not afraid of their cutting off our food, as it would save us the enormous mass of fertilisers and feeding-stuffs we have to carry into Ireland through the de Valera-aided German blockade.'
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Note that when Churchill uses the term de Valera-aided, he is only referring to the fact that the Irish are aiding the German blockade by not allowing British ships and planes to base in southern Ireland.
In all of this Churchill kept the American President informed.
Former Naval Person to President Roosevelt 13/12/1940
'In the meanwhile we are so hard pressed at sea that we cannot undertake to carry any longer the 400,000 tons of feeding-stuff and fertilisers which we have hitherto convoyed to Eire through all the attacks of the enemy. We need this tonnage for our own supply, and we do not need the food which Eire has been sending us. We must now concentrate on essentials, and the Cabinet proposes to let de Valera know that we cannot go on supplying him under present conditions. he will of course have plenty of food for his people, but they will not have the prosperous trading they are making now. I am sorry about this, but we must think of our own self-preservation, and use for vital purposes our own tonnage brought in through so many perils. Perhaps this may loosen things up and make him more ready to consider common interests. I should like to know quite privately what your reactions would be if and when we are forced to concentrate our own tonnage upon the supply of Great Britain. We also do not feel able in present circumstances to continue the heavy subsidies we have hitherto been paying to the Irish agricultural producers. You will realise also that our merchant seamen, as well as public opinion generally, take it much amiss that we should have to carry Irish supplies through air and U-boat attacks and subsidise them handsomely when de Valera is quite content to sit happy and see us strangled.'
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