Arrests of Sinn Féin leaders

During the night of 17/18 May 1918 police and troops carried out a round-up of the leaders of Sinn Féin throughout Ireland. At Greystones in County Wicklow they arrested the party’s president, Éamon de Valera; in Dublin its founder, Arthur Griffith, the secretary Darrell Figgis and the MP William Cosgrave; at about one in the morning in Rathmines, Constance Markievicz; and in Belfast, among others, Denis McCullough. Those arrested also included the MPs Joseph McGuinness and Count George Noble Plunkett, father of an executed leader of the Easter Rising, as well as Maud Gonne. Held without trial under the Defence of the Realm regulations, the detainees were quickly taken to England and Wales. The men were held in prisons including those at Gloucester, Lincoln and Usk, the women in Holloway prison in London. According to some sources 73 people were deported in the first wave. Others were arrested over the following days, and by other estimates the arrests took in about 150 people.

The “German Plot”

On the morning of 18 May a proclamation was issued by the new Lord Lieutenant, Field Marshal John French, countersigned by the Chief Secretary, Edward Shortt. It declared that some inhabitants of Ireland had been in “treasonable communication with the Germans”, and called on loyal subjects to help suppress the conspiracy. At the same time it announced that the authorities would encourage voluntary enlistment, in the hope that Ireland’s contribution to the armed forces could be made up without compulsion. Many commentators read this as a sign that the government was retreating on conscription, which since April could be extended to Ireland.

The immediate pretext was the case of Joseph Dowling. This former British soldier, taken prisoner and recruited in Germany into the Irish Brigade organised by Roger Casement, was landed from a German submarine on a small island off the coast of County Clare on 12 April 1918 and soon caught. He claimed that the Germans were preparing an expedition to Ireland. The head of naval intelligence, Admiral William Reginald Hall, and the head of Scotland Yard’s Special Branch, Basil Thomson, believed him and persuaded the government to intern the entire leadership of Sinn Féin. For weeks the movement had been leading the campaign against conscription, and after the failure of the Irish Convention the cabinet was inclining towards a harder policy.

Evidence and consequences

Sinn Féin learnt of the planned round-up in advance. Michael Collins and Cathal Brugha escaped arrest. Some of the leaders, de Valera among them, deliberately allowed themselves to be taken, counting on a propaganda gain. On 25 May the British government published an official statement meant to prove the existence of the plot. It was received coolly even at Westminster, and critics pointed out that it concerned mainly contacts with Germany in 1914–1916, from the time of Casement and the Aud, rather than the leaders arrested in May. Even supporters of a hard line, such as General Nevil Macready, were disappointed by the lack of clear evidence and the flimsy legal basis for the detentions.

Historians still argue over whether the “German Plot” was deliberately manufactured propaganda or the result of honestly handled but faulty intelligence. They agree, however, that the round-up backfired on the government. The most moderate leaders of the movement ended up behind bars, and the leadership passed to the advocates of armed struggle grouped around Collins. As early as 20 June the imprisoned Griffith won the East Cavan by-election, and on 3 July the authorities declared Sinn Féin, the Irish Volunteers, Cumann na mBan and the Gaelic League dangerous organisations. In the December 1918 election Sinn Féin won an overwhelming majority of Irish seats. De Valera escaped from Lincoln prison in February 1919, and the remaining internees were released in March.