Plan W, during World War II, was a plan of joint military operations between the governments of Ireland and the United Kingdom devised between 1940 and 1942, to be executed in the event of an invasion of Ireland by Nazi Germany.
Although Ireland was officially neutral, after the German invasions of 1939–40 that resulted in the defeat of Poland, the Low Countries and France, the British recognised that Germany planned an invasion of Britain (Operation Sea Lion) and were also concerned about the possibility of a German invasion of Ireland. German planning for Operation Green began in May 1940 and the British began intercepting communications about it in June. The British were interested in securing Ireland, as its capture by German forces would expose their western flank and provide a base of operations for the Luftwaffe in the Battle of the Atlantic and in any operations launched to invade Great Britain as part of Operation Sea Lion.
Irish-British co-operation was a controversial proposal for both sides, as most members of the Irish political establishment had been combatants in the Irish War of Independence between 1919 and 1921. However, because of the threat of German occupation and seizure of Ireland and especially the valuable Irish ports, Plan W was developed. Northern Ireland was to serve as the base of a new British Expeditionary Force that would move across the Irish border to repel the invaders from any beach-head established by German paratroopers. In addition, coordinated actions of the Royal Air Force and Royal Navy were planned to repel German air and sea invasion. According to a restricted file prepared by the British Army's "Q" Movements Transport Control in Belfast, the British would not have crossed the border "until invited to do so by the Irish Government,"Fisk pp. 237–238. and it is not clear who would have had the operational authority over the British troops invited into the State by Éamon de Valera.de Valera had agreed to the plan "wholeheartedly" although was more reluctant in private about which would be worse – a German or a British occupying force. The document added that most people in Ireland probably would have helped the British Army, but "there would have been a small disaffected element capable of considerable guerrilla activities against the British."Fisk pp. 237–238.
By April 1941 the new British Troops in Northern Ireland (BTNI) commander, General Sir Henry Pownall, extended his planning for a German invasion to cover fifty percent of the entire Irish coastline. He believed that German troops were likely to land in Cork, Limerick, Waterford, Westport, Galway, Sligo, and County Donegal, i.e. on the southern or western coasts. British Army personnel also carried out secret intelligence-gathering trips to glean information on the rail system south of the border.
Context
Political context and early planning Discussions over the possible German invasion of Ireland had been ongoing in Britain since the beginning of 1939. In June 1940, Britain's political and military establishment had witnessed the seemingly invincible German Blitzkrieg which led to the defeat of Poland, the Low Countries, and France, and the retreat of the British Expeditionary Force from Dunkirk. The British suspected that, following their defeat in France, the next step would be a German invasion of Britain – Operation Sea Lion. They did not know, but also suspected, that there was a plan to invade neutral Ireland – Operation Green.
In this context, they embarked on the policy of planning, together with the Irish authorities, for the defence of the island. This was a controversial proposal as most of the Irish political establishment had been combatants in the Anglo-Irish War against the British between 1916 and 1921. For instance, the Fianna Fáil politicians in the Irish government included Éamon de Valera, Seán T. O'Kelly, Seán Lemass, Gerald Boland, Oscar Traynor, Frank Aiken, Seán MacEntee, and Thomas Derrig, all of whom had been active against the British. On the British side, Winston Churchill, and many senior members of his administration had forcibly opposed their bid for an independent Irish state, including setting up the controversial Black and Tans to oppose militant separatism.
However it was not so different from de Valera's position in 1921. During the debates on the Anglo-Irish Treaty in late 1921, de Valera had submitted his ideal draft, known as "Document No.2" which included: 2. That, for purposes of common concern, Ireland shall be associated with the States of the British Commonwealth, viz: the Kingdom of Great Britain, the Dominion of Canada, the Commonwealth of Australia, the Dominion of New Zealand, and the Union of South Africa. 4. That the matters of "common concern" shall include Defence, Peace and War, Political Treaties, and all matters now treated as of common concern amongst the States of the British Commonwealth, and that in these matters there shall be between Ireland and the States of the British commonwealth "such concerted action founded on consultation as the several Governments may determine". 8. That for five years, pending the establishment of Irish coastal defence forces, or for such other period as the Governments of the two countries may later agree upon, facilities for the coastal defence of Ireland shall be given to the British Government as follows: (a) In time of peace such harbour and other facilities as are indicated in the Annex hereto, or such other facilities as may from time to time be agreed upon between the British Government and the Government of Ireland. (b) In time of war such harbour and other Naval facilities as the British Government may reasonably require for the purposes of such defence as aforesaid. 9. That within five years from the date of exchange of ratifications of this treaty a conference between the British and Irish Governments shall be held to arrange for the handing over of the coastal defence of Ireland to the Irish Government unless some other arrangement for naval defence be agreed by both Governments to be desirable in the common interest of Ireland, Great Britain, and the other associated States.
De Valera had proposed that a final settlement between Ireland and Britain would give regard to Britain's future maritime defence, in recognition of Britain's longstanding fear of invasion from the west.
Among the Irish opposition party's Fine Gael leadership, W. T. Cosgrave, Desmond Fitzgerald, Richard Mulcahy and several others had also fought in the previous Irish Civil War and the Irish Army had thousands of veterans from that conflict. Major General Joseph McSweeney, General Officer Commanding (GOC) of Irish Army's Western Command in 1940, had been in the GPO during the Easter Rising. Colonels Archer and Bryan of Military Intelligence G2 had also fought in the conflicts. The IRA member Tom Barry volunteered his services to the Irish Army in 1939 and became operations officer in the 1st Division.
British strategic assessment
After the invasion of Belgium and the Netherlands, the British were convinced that an invasion of Ireland would come from the air, via paratroopers. They were not satisfied with the Irish government's defence capability, particularly against airborne troops. The topic of reoccupying the 26 counties of Ireland had been a matter of political conversation in Britain since the beginning of the war. In June 1940, Malcolm MacDonald offered to "give back" the six counties comprising Northern Ireland – an offer of Irish unity – if Ireland would join with the Allies, but the offer was not taken seriously. The same month Major General Bernard "Monty" Montgomery was busy planning the seizureSee Robert Fisk's In Time of War: Ireland, Ulster and the Price of Neutrality, 1939–1945 (1996). London: Gill & Macmillan. — (1st ed. was 1983) p. 241. Cobh was to be attacked by the British 3rd Infantry Division so that the Cork Harbour could be used as a naval base for the anti-submarine war in the Atlantic, the plan was eventually dropped as one division was not considered enough of a force to reoccupy this part of the State. of what he referred to as "Cork and Queenstown (Cobh) in Southern Ireland" (sic). Winston Churchill was to also refer to the "... most heavy and grievous burden placed upon Britain by the Royal Navy's exclusion from the three Treaty Ports [in Ireland]."Fisk p. 242 The Economist reported that Britain should seize the ports if they become "a matter of life and death". The remarks were made in the face of mounting losses in the Battle of the Atlantic.
Attempts were also made on 26 June 1940 to split the consensus in Ireland over the neutrality policy via a possible coup attempt. An approach was made to Richard Mulcahy (leader of Fine Gael at the time) by an Irish-born ex-British Army lieutenant colonel who was a city councillor in the State. Mulcahy recorded that the ex-officer:
"...called to say that 'the people in the North are prepared to make a military convention with this country [Ireland] without reference to the Northern Government... He wanted someone to go up there from here unofficially, to speak to someone in authority and say how the land lay. In reply to questioning, he stated that the people he referred to were the British Army authorities in the North."
This was in effect a proposal for a joint military command of all of Ireland, which the unidentified ex-British Army lieutenant colonel said had been stimulated after discussion with "important members of the British Army in the North of Ireland."The colonel was a friend of Maffey's and the proposal had been made on the same day de Valera had been offered terms of unification with a joint defence council of Ireland and Northern Ireland. It is possible that the simultaneous discussions could have been an attempt to pressure de Valera, the Taoiseach. Unionist politician Sir Emerson Herdman also called to speak with de Valera about obtaining "unity of command" and to ask if Ireland would enter the war in return for an end to partition. Herdman appears to have been acting on behalf of Craigavon, but when de Valera rebuffed him, he was of the view that:
"the only thing to do now for Britain is to send in powerful forces here, and prevent this country being seized, or prevent them [the British] having to use and lose large numbers of troops in putting the Germans out if they got here."Fisk pp. 243–244.
Therefore the W-Plan had a dual purpose: a joint plan of action in the event of a compliant Ireland, an invasion plan in the event of a German invasion and subsequent resistance.
Knowledge of German planning Planning began for Operation Green in May 1940, and the British had intelligence about it beginning in around June of that year. The British were interested in securing Ireland as its capture by German forces would expose their western flank, and provide a base of operations for the Luftwaffe in the Battle of the Atlantic and in any operations launched to conquer Britain as part of Operation Sea Lion. The British suspected that the Germans target for an invasion attempt would be Cork, particularly Cork Harbour with the naval base at Cobh because it was the nearest to Luftwaffe bases in north west France.
Irish defence status