London and Dublin have signed an updated Memorandum of Understanding (MoU) on bilateral defence cooperation. Defence Secretary John Healey and Ireland’s Minister for Defence Helen McEntee signed the document on 13 March 2026, alongside the UK–Ireland Leaders’ Summit in Cork. The Ministry of Defence said the refresh focuses on enhanced maritime cooperation, strengthened cyber defence, air‑domain information sharing, and exploration of joint procurement and Government‑to‑Government sales. It also aims to improve protection of critical undersea infrastructure and to develop better response mechanisms to maritime security incidents, while boosting information sharing to build common situational awareness and resilience. The announcement additionally highlights continued collaboration in UN peacekeeping, crisis management and humanitarian operations, expanded cooperation on training and military education, and ongoing support for Ukraine as part of a ‘Coalition of the Willing’. (gov.uk)
Ireland has moved in step on maritime security at home. On 11 March, Minister McEntee secured Cabinet approval to begin drafting legislation to give the Defence Forces new powers to safeguard Ireland’s maritime domain and sovereign rights, in line with UNCLOS. Separately, reporting in The Irish Times flagged a forthcoming maritime security plan that would consider an EU monitoring hub to track critical infrastructure in the North Atlantic. Together, these initiatives frame the operational backdrop for bilateral cooperation on undersea cables, interconnectors and incident response. (gov.ie)
Cyber and air elements are designed to tighten reciprocal flows of information between authorities, improving the shared picture of threats and abnormal activity. For operators of essential services and for aviation stakeholders, the direction of travel points to more formal cross‑border threat data feeds and alignment of resilience exercises, subject to implementing arrangements now to be set by departments.
The procurement strand is framed as exploratory. Joint orders and potential Government‑to‑Government sales could, where requirements align, deliver economies of scale and simplify through‑life support across small fleets. The announcement does not set timelines or programmes; the next signal will be whether officials table pilot projects or coordinated market engagements.
The refreshed cooperation framework replaces the 2015 MoU signed by then Defence Secretary Michael Fallon and Irish Minister Simon Coveney. In 2015, ministers in Dublin characterised that MoU as a non‑binding arrangement that did not alter Ireland’s policy of military neutrality. (gov.uk)
Delivery will rely on existing channels rather than new structures, with crisis‑management exercises, training courses and staff exchanges acting as the primary vehicles. The immediate practical work is to assign lead directorates for the four strands, set data‑sharing protocols for cyber and air information flows, and formalise incident‑response playbooks at sea.
Governance context in Dublin is relevant. Helen McEntee has held the foreign affairs and defence portfolios since November 2025 and has set out plans to expand defence capacity through 2028, with the 2026 allocation at approximately €1.17 billion. Concentrating these responsibilities in one ministerial office may streamline follow‑through across maritime, cyber and procurement workstreams. (ireland.representation.ec.europa.eu)
Politically, the timing signals sustained attention at leader level in both capitals. Micheál Martin currently serves as Taoiseach, with further operational detail expected from the Ministry of Defence and Ireland’s Department of Defence as workstreams are defined. (gov.ie)