The conventional view of the British Army’s two Ireland campaigns - first in Southern Ireland [1919-1921] and then, two generations later, in Northern Ireland [1969-2007] – are that the first was an outright defeat and the second, a military stalemate. This book challenges these judgements. Deploying hitherto unused or misunderstood archival materials, it documents how in both campaigns the Army, acting in support of the Royal Irish Constabulary and the Royal Ulster Constabulary, respectively, achieved considerable success at both tactical and operational levels. However, the persistence of perverse, self-harming ‘operating codes’ on the part of generations of the British policy elite meant that the strategic outcomes bore little relation to the operational successes achieved against insurgency and terrorism. Professor Sloan shows how over the span of a century, the Whitehall/Westminster nexus twice seized political defeat from the jaws of military victories achieved for the Crown by the Army. He finds and names the guilty men. This book is explosive. It will be uncomfortable but essential reading on both sides of the Irish Sea.“Sloan’s gripping book uncovers a century of dirty work by dirty men in Ireland. Exceptional” - Professor Gwythian Prins, Fellow Emmanuel College Cambridge and Emeritus Research Professor LSE. “Sloan’s strategic history of the Army’s campaigns in Ireland and Northern Ireland is compelling. His understanding of the ‘operating codes’ makes it a must read!” - Dr Aaron Edwards, Senior Lecturer in Defence and International Affairs, Royal Military Academy Sandhurst, UK.