- Ireland and the UK signed a “refreshed” Memorandum of Understanding (MoU) to enhance bilateral defence cooperation
- Russia continues to pose a threat to European security through hybrid activity
- Both nations will need to cultivate a stronger picture of threats in the air, on and below the sea
Irish Defence Minister Helen McEntee and UK Defence Secretary John Healey signed a refreshed MoU at the end of last week, committing to new areas of defence cooperation.
In its announcement on 13 March, the UK Government said the two nations intend to address “common threats” in the air, cyber and maritime domains. Concern for these shared vulnerabilities are prompted by Russian interference and hybrid activity, even if neither government has said so directly during the signing.
One notable development in this latest bilateral agreement are plans to launch joint procurement initatives in order to expand their defence capabilities as cheaply as possible.
For Ireland, whose defence investment has always been modest, the country is beginning to increase its territorial security to meet the Russian threat, particularly at sea.
In December 2025, for example, an incursion by four drones, which are believed to have been of Russian origin, exposed Irish military deficiencies. The units were observed by the Irish naval vessel LÉ William Butler Yeats near Howth; the crew is believed to have considered engaging the drones with the vessel’s 20 mm anti-aircraft gun, but this was assessed to be ineffective.
Meanwhile, the cash-strapped UK Government has had to overcome fierce disillusionment since the end of 2025. The Ministry of Defence (MoD) has routinely delayed the long-awaited Defence Investment Plan, now having to make difficult “trade-offs” which will likely lead to cancelled programmes despite the ambitious recommendations made in the Strategic Defence Review last year.
Ten years on
The latest bilateral agreement builds on the original version signed by predecessors, Minister Simon Coveney and Secretary Michael Fallon in 2015.
“It is appropriate that, after ten years… we take the opportunity to refresh our Memorandum of Understanding,” McEntee stated, adding that the refresh continues to “respect… fully the differing policy positions and security arrangements”, namely Ireland’s neutrality and unwillingness to join the Nato military alliance.
Both the original and updated documents take into account matters such as training, education and staff exchanges, among other topics.
There has also been a notable uptick in defence discussions between the two nations in 2025.
The UK Permanent Secretary visited Ireland in January; the Chief of the Defence Staff (CDS) visited in February, marking the first visit of a CDS to Ireland since 2016; while the Second Permanent Secretary visited in April.
Maritime cooperation
The most obvious shared vulnerability for the two neighbouring countries is the surface and sub-surface threat from Russian naval platforms in their respective waters.
Both countries host significant infrastructure, including subsea cables in their exclusive economic zones, which, according to Ireland’s National Maritime Strategy, exposes the country to “an additional degree of risk from both State and non-State actors.”
Both navies are pursuing anti-submarine warfare (ASW) capabilities.
The UK is jointly procuring Type 26 ASW frigates from BAE Systems while the republic has spent several million euros on a towed array sonar system in a deal with Thales last year. But Ireland is also looking to increase its operational bandwidth with more ships, which may include a new Multirole Combat Vessel that would host a relatively smaller ASW system.
The UK Government and Babcock, a British naval supplier, are eager to find export opportunities for the Type 31 multipurpose frigate. The vessel, which displaces 5,700 tonnes, would meet Irish naval requirements with its large mission bay space, which can fit up to 20 ISO containers.
Likewise, a speedy delivery may be expected since Roysth shipyard has reached a rhythm in production, having ironed out the kinks during the manufacture of the Royal Navy’s first three Inspiration-class ships.
The Irish Naval Service also utilises uncrewed aerial vehicles (UAVs) at sea. While these units serve to provide sight beyond the horizon, it may prove cost-effective for the both navies to jointly procure a number of autonomous surface or underwater vehicles.
This avenue has proven popular for the UK in its own naval renewal. Since the MoD cannot afford larger conventional warships, one senior minister told this reporter that uncrewed vehicle orders may continue to support work at British shipyards, such as Babcock’s Rosyth facility in Scotland.
Aerial information sharing
“As an island nation,” McEntee considered during a Joint Committee on Defence and National Security on 26 February, “we must be ambitious about our air defence capabilities.”
In particular, the minister referred to plans to purchase radar systems with different ranges from land and sea. However, the minister emphasised that these projects may “take a long time”.
Other offensive capabilites, such as combat aircraft, a capability the Irish Air Corps lack, require a long range radar system to operate effectively according to GlobalData defence analysis. The analytics firm also indicated that the Irish Defence Department may purchase eight to 12 fighter aircraft in the coming years. But for now, McEntee did not directly answer a question put to her during the committee session on plans for procuring combat aircraft in the near future.
Across the channel, the UK has experienced trouble with constructing its own aerial picture. Though last year the MoD procured several Land Ceptor launcher units, its aerial picture is still lacking.
In particular, the UK is still waiting to replace its E-3 Sentry fleet (which retired in 2021) with three delayed E-7 Wedgetail Airborne Early Warning aircraft later this year. The first aircraft is currently undergoing intensive testing before entry.
Since Ireland de facto relies on the Royal Air Force for support in this area, the inability of the UK to detect complex modern threats – such as low-flying cruise missiles or stealthier adversaries – at long range is significantly diminished across the region. This is made worse when one considers the prevalence of mixed salvos in contemporary warfare, first implemented by Russia in its invasion of Ukraine, but also by Iran amid the conflict in the Middle East.
