Political violence emanating from internal immigrant communities is not new to European states. The United Kingdom, in particular, has dealt with reoccurring security threats from its Irish-born population, most notably during a destructive bombing campaign by the Provisional Irish Republican Army from 1973 to 1996. Irish Republican separatists had already been active in the United Kingdom a century earlier. The Fenian Dynamite Campaign of 1881–85 in many ways foreshadowed modern terror attacks. Bombs targeted symbolic state buildings and civic institutions, including the House of Commons, London Bridge, the London Underground, the Tower of London, and the headquarters of the Metropolitan Police's Special Irish Branch. These Fenian bombers have received extensive scholarly attention, most recently in Niall Whelehan's fascinating monograph, The Dynamiters, Irish Nationalism and Political Violence in the Wider World, 1867–1900 (2012). Far less interest has been shown in the Fenian Brotherhood's successor, the Irish Republican Army (IRA), and its operations on British soil during the Irish Revolutionary period (1919–23). Early work on the IRA in Britain by Michael Hopkinson and the late Peter Hart (who produced two outstanding journal articles on the subject) has not been followed up. Gerard Noonan's new monograph, The IRA in Britain, 1919–1923, therefore, has an opportunity to fill a lacuna in the literature.

Noonan has produced a relatively narrow military history of the republican campaign in Britain. Chapters explore IRA organizational structures, gunrunning networks, and sabotage operations from 1919 through 1923. He has done a fair job of reconstructing the republican war machine in Britain, tying together numerous covert and frayed strands of subversion. Perhaps the volume's most significant achievement lies in the detailed listing of IRA actions during the period. Noonan catalogues extensive sabotage operations in and around London, Kent, Yorkshire, Glasgow, Birmingham, Liverpool, Manchester, Sheffield, and Tyneside. Most frequently IRA Volunteers carried out arson attacks on warehouses, factories, farms, timber yards, and the homes of police constables serving in Ireland. While shooting affrays were relatively rare, the London IRA planned to assassinate members of the British Cabinet in 1920, and it did shoot Field Marshal Sir Henry Wilson dead in 1922. Overall, Noonan conveys the wide scope of republican efforts to bring the war in Ireland “home” to Great Britain. Readers will gain a greater appreciation of the strength, spread, and potential of the British IRA during this period.

Perhaps the book's most interesting material relates to republican gunrunning in Britain. Drawing together scattered pieces of evidence, Noonan has found significant levels of arms smuggling from a diverse number of urban areas in England and Scotland. Subject specialists will be intrigued by the high quantities of explosives secured by the IRA from various mines, often located in Lancashire and Scotland. Noonan's figures also confirm the IRA's poor record of acquiring rifles and rifle ammunition in Britain. Strangely, he downplays the significance of this finding, arguing that the IRA in Ireland killed most of its victims with pistols and shotguns rather than rifles. Yet this interpretation fails to account for the rapid expansion of IRA flying column operations, which depended on rifles and were hampered by severe ammunition shortages (in 1921, the IRA as a whole possessed fewer than 3,300 rifles, with a paltry average of 43 rounds per weapon). Thus, the inability of the IRA in Britain to export rifles and ammunition altered the trajectory of the Irish War of Independence. The arms issue also factored in the repudiation of the IRA headquarters by its frustrated provincial leadership in the run-up to the Irish Civil War.

Such incomplete analysis is a reoccurring problem with The IRA in Britain. For example, Noonan flags local leadership as a key factor in the varied military performances of IRA units without providing biographical backgrounds on the leaders. He also fails to draw crucial distinctions. For instance, the Scottish IRA expressed a leftwing identity that distinguished it from the rest of the British IRA, yet its political ideology is not scrutinized. There is little attempt to address the radicalization process of IRA activists, especially British-born (English, Scottish, and Welsh) Irish republicans who committed high crimes against the country of their birth. Indeed, this study demonstrates a rather shallow grasp of the cultural and economic complexities of the Irish community in Great Britain. Overall, Noonan inadequately interrogates his findings, which prevents him from developing sufficiently robust arguments.

Noonan's research, like his analysis, is uneven. The primary work undertaken in Ireland is fairly thorough, with particularly good use made of the National Library's recently acquired Art Ó Bríain collection, which is emerging as a key holding for Irish Revolution scholars. Much of the information on arms smuggling comes from Noonan's painstaking review of the massive Richard Mulcahy Papers, located at University College Dublin. Less success is achieved across the water. While some of the relevant Cabinet and Home Office records are accessed, Noonan has made little headway with nongovernmental collections pertaining to British-based trade unions, anticolonial movements, and left-wing parties that interacted with Irish republicans. The book's bibliography also lacks some key texts, most strikingly, Keiko Inoue's unpublished 2009 PhD dissertation, “Political Activity of the Irish in Britain, 1919–1925.”

The IRA in Britain has illuminated numerous hidden elements of the Irish Republican campaign from 1919 to 1923, and it can be recommended as a basic survey of republican paramilitary activity in Britain. However, too often Noonan does not adequately explain the relevance, context, or subtleties inherent in such operations. As a result, the IRA in Britain 1919–23 still awaits the writing of its definitive history.