ABSTRACT Intelligence is crucial to success in counter-terrorism, and successful intelligence work involves effective liaison between and within all the organisations involved. Scholars rarely address intelligence in counter-terrorism other than through case studies, while studies of intelligence in counter-insurgency and studies of international intelligence liaison emphasise the value of intelligence liaison with little attention to how it works in practice. This article substantially expands existing knowledge and understanding by focusing on intelligence coordination within Northern Ireland in the 1990s. It draws on heretofore unexploited, yet voluminous, original material. It analyses the contribution that computerisation made to inter-agency liaison, the contribution the Northern Ireland Prison Service made to intelligence work, the role played by intra- and inter-agency structures and the valuable work that the right individuals in the right posts can do. This article thereby provides a broader and deeper understanding of the challenges faced by state agencies and how some of these were overcome to facilitate inter- and intra-agency intelligence liaison in Northern Ireland in the 1990s. It therefore contributes to emerging theory that seeks to explain intelligence.