Formerly known as J2, the unit has adopted the name Irish Military Intelligence Service (IMIS) and has recently moved into a newly constructed, purpose-built headquarters in Dublin. While most of its operations remain highly classified – more so even than the Garda’s Security and Intelligence Service – the latest report from the judge tasked with overseeing State surveillance activities offers a rare, albeit limited, glimpse into its current operations.

Mr Justice Tony O’Connor stated in March that IMIS had relocated to a secure facility built to “top secret clearance and security specifications”. Sources indicate the site is within McKee Barracks in Dublin and includes advanced systems for handling intelligence from NATO and EU partners.

The unit’s former base, also located in McKee Barracks, has been handed over to the newly formed Defence Forces Joint Cyber Defence Command, which took possession in early May.

The overhaul is taking place in line with a commitment in the programme for government to review military intelligence structures to ensure they are “optimised to protect national security”. Mr Justice O’Connor’s report is the first official public document to use the service’s new name, although internal Defence Forces planning documents continue to refer to the former designation, J2.

IMIS is responsible for safeguarding State security and the integrity of State agencies, including Defence Forces personnel deployed overseas. It operates with significantly fewer resources than its Garda counterpart, which holds primary responsibility for domestic security.

Much of the intelligence obtained by IMIS is sourced from international military and intelligence bodies, including the European Union Intelligence and Situation Centre and NATO’s Battlefield Information Collection and Exploitation System. In some cases, however, the service conducts its own intercepts and communications surveillance.

Mr Justice O’Connor noted that such surveillance is used exclusively for intelligence gathering rather than for criminal prosecutions, and that subjects of interception are never informed. These operations fall under the remit of the Interception of Postal Packets and Telecommunications Messages Act 1993, which IMIS considers a “valuable and significant source of intelligence”.

The judge also highlighted the service’s growing reliance on Section 6 of the Communications (Retention of Data) Act 2011, which permits a senior Defence Forces officer to request access to customer data held by service providers “for the purpose of safeguarding the security of the State”.

However, IMIS currently lacks legal authority to intercept communications conducted over internet-based platforms such as WhatsApp, Gmail or Facebook Messenger. The Defence Forces have urged the Department of Justice to amend legislation to address this shortcoming.

According to the judge’s report, IMIS has also called for new statutory powers to compel service providers to comply with data requests. Without such authority, international firms may refuse to cooperate with military intelligence.

The judge also supported recommendations from the 2022 Commission on the Defence Forces calling for legislation to clarify the “role, function and powers” of military intelligence. He recommended Ireland benchmark its military intelligence arrangements against those of comparable European countries.