In time of revolution, hushed meetings can happen in the most unlikely of places. In revolutionary Dublin, intelligence policemen followed republican suspects from cafe to newsagent and everywhere in between. At the National University of Ireland, Earlsfort Terrace, both students and staff had radicals in their midst.

That some prominent nationalists worked in academia at the university ensured that more than just academic issues were discussed on campus. P.J Paul, Officer Commanding the East Waterford Brigade in the intensifying guerilla war in the Irish countryside, recalled meeting Richard Mulcahy in his office in the university in 1921 to discuss the course of the conflict, before being taken to another room in the University:

which I remember had the name on the door saying that it was the room of Professor Eoin McNeill. There I met Emmet Dalton and a man named Cronin, an American, and another American who was with him. I was shown a specimen of the Thompson sub-machine guns which I learned were being smuggled in from America in some quantities. The two Americans were the experts on the gun and they demonstrated how it worked and explained its mechanism.

The Thompson submachine gun, or the Tommy Gun, was invented in 1918 by United States Army officer John T. Thompson, coming onto the market in 1921. The gun is synonymous in popular culture with Prohibition-era Gangsterism in the U.S, recalling Al Capone and incidents like the St. Valentine’s Day Massacre. The so-called ‘Chicago Piano’ has maintained a lasting place in popular memory owing to television shows like Boardwalk Empire and Peaky Blinders. Still, before the gun was ever utilised in the chaos of mob warfare, it was tested by the Irish Republican Army in Marino and fired for the first time in a military capacity in an IRA ambush in Drumcondra. For the Irish republican movement on both sides of the Atlantic, the gun would represent a definitive turning point in the war in Ireland. Internationally, it is remembered as “the gun that made the twenties roar.” In Ireland, it arrived late in the War of Independence, but would have a formative influence in subsequent political turmoil.

Developing and selling the Tommy Gun:

For General John T. Thompson, the journey towards a “one-man, hand-held machine gun” began in 1916 with the foundation of the Auto-Ordnance Company. Financially backed by American insurance magnate Thomas Fortune Ryan, a supporter of the Clan na Gael Irish-American Fenian movement, Thompson’s gun prototype was initially known as ‘The Annihalator’. Unsurprisingly, the gun attracted the attention of Irish republican representatives in the United States, who supplied IRA GHQ in Dublin with as much information as possible on the Tommy Gun and its capabilities. GHQ relied on number of channels – including the Liverpool docks and European arms dealers – to equip the IRA in its guerilla campaign, and attempted to remain abreast of developments in arms on the continent and beyond.

The Tommy Gun was not cheap, retailing at $225 a piece. Likewise, the absence of suitable ammunition in Europe would create real headaches. Still, greatly encouraged by reports of the guns capabilities, IRA GHQ encouraged those in America to secure quantities of the weapon. Having received cuttings on the gun from Harry Boland in the U.S, Michael Collins sent a memo to the Quarter Master General of the IRA in January 1921, writing “I wonder if you saw the attached having reference to the submachine gun. It looks like a splendid thing certainly. I’d like to know what it costs.”

By May 1921, small quantities of the gun were beginning to arrive in Ireland, along with Major James Dineen and Captain Patrick Cronin, former officers of the US Army who were to train IRA men in their use. Oscar Traynor of the IRA’s Dublin Brigade later recalled:

The first introduction of these guns followed the arrival of two ex-officers of the American Army, one was Major Dineen and the other, whose rank I forget, was named Cronin. These two men were made available to the Brigade for the purpose of giving lectures and instructions in the use of the Thompson submachine guns. The lectures, which were given to selected men of the Dublin Brigade, consisted in the main of taking the gun asunder, becoming acquainted with the separate parts and securing a knowledge of the names of these parts, the clearance of stoppages, as well as the causes of these stoppages. In the early stages it was not possible to give practical demonstrations of the shooting powers of these weapons, but the handling of the guns, together with the methods of sighting, made the men reasonably proficient.

In the presence of Dineen and Cronin, the gun was test fired underground at the Casino in Marino before a select audience of IRA men. Vincent Byrne recalled that “It was Cronin who gave the demonstration. Standing back a few yards, he fired at a tin can. The first shot lifted it into the air and he kept hitting it in mid-air. The Big Fella and Mulcahy were delighted at the results and our only wish was that we had plenty of them.” Tom Barry of the IRA’s 3rd West Cork Brigade fired the gun at Marino too, but the massive roar of the gun led to fears the men would be discovered. All in attendance left impressed by its remarkable capabilities.

“Our Latest Ally”

Shortly afterwards, on 16 June 1921, the IRA made history with the first use of the Thompson submachine gun anywhere in the world in a combat situation. As a train of soldiers from the West Kent Regiment passed through Drumcondra, a waiting IRA ambush party opened fire, wounding three soldiers in the process. Brazenly, the internal IRA publication An tÓglach reported on the gun as “our latest ally”, telling Volunteers that “with such a superb weapon available it is up to the individual soldier to lose no opportunity of learning all he can about the construction, use and care of it.” The gun, the newspaper noted, “is the latest improvement in quick-firing weapons. It has many advantages over any other type of machine gun and in particular over those used by the British – Lewis, Hotchkiss and Vickers.”

Getting the weapon into Ireland involved a degree of collusion with sympathetic authorities in the United States. One Bureau of Military History Witness Statement references a New York arms dump which the NYPD were not alone aware of, but sometimes carried Irish republicans to and from. Limerick man Edmond O’Brien, active in the Volunteers since their foundation and hiding in the United States as a result of his War of Independence service in Munster, recalled in his statement that:

The method of getting his stuff over to Ireland was by smuggling in small lots on liners and cargo vessels by the connivance and through the good offices of friendly seamen and dock labourers. A number of these were always in touch with Boland, Nunan and Pedlar, and faked passes were provided to Jim Scanlon and myself to get us through the docks and on to the ships with suitcases filled with arms and ammunition.

The IRA’s faith in the weapon is evident from the sheer number of Tommy Guns sanctioned for purchase, with more than 650 of the model acquired. Unfortunately, the majority of this load never reached Ireland, intercepted on board the freighter East Side, sailing to Ireland from New Jersey. A suspicious crew member stumbled on the cargo, alerting the authorities. A staggering 495 Tommy Guns found their way into the hands of the NYPD and the FBI. In his history of the Tommy Gun, Martin Pegler notes that “as can be imagined, this event stirred up a political hornets’ nest in America, Britain and Ireland. Agents from the US Bureau of Investigation, headed by a young man named J. Edgar Hoover, descended en masse on the vessel….There was little difficulty in tracing exactly who had ordered the guns, for the serial numbers had not been erased on all of them.”

Tommy Guns 1-40 were prototypes of the weapon, making it all the more remarkable that in museums in Ireland today are Tommy Guns with serial numbers in the forties and fifties. In many ways, it was the IRA who first fired the gun in anger, and it would remain synonymous with the organisation into subsequent decades, indeed Tommy Guns brought into the country in the 1920s were still in use when the northern Troubles erupted.