British surveillance ship to monitor subsea cables in Irish economic zone

Irish Naval Service currently has no way of monitoring cables security

Britain’s Royal Navy is to launch a surveillance ship to monitor and secure vital subsea cables in the Irish Exclusive Economic Zone (EEZ).

The collection of communications cables that run along Ireland’s south coast and that connect Ireland and the United Kingdom with North America are viewed by security officials as increasingly vulnerable to attack or sabotage. The Irish Naval Service currently has no method of monitoring the cables.

Their importance came into focus in January when Russia announced it was conducting naval exercises directly above such cables in the Irish EEZ. The exercises were later moved farther out into the Atlantic following protests from the Government. Russia is believed to possess naval vessels capable of cutting or interfering with underwater cables.

In response to the threat, the UK government is building a multi-role ocean surveillance ship designed to protect undersea cables in the north Atlantic. Military sources confirmed this would include operations in the Irish EEZ. Under maritime law, countries are permitted to operate in other nations’ EEZs as long as they do not enter their territorial waters, which typically extend 19km out from the coast.


The 15-person vessel is in the concept and assessment phase and is scheduled to launch in 2024. It will be capable of launching undersea drones which then monitor undersea cables.

A Department of Defence spokesman said there are currently no plans for the Irish and British governments to co-operate on the project.

A Royal Navy spokesman said the ship will operate in the north Atlantic where it will “safeguard critical infrastructure”. Asked about possible co-operation, he said the Royal Navy and Irish Naval Service “have a close and professional relationship” which was highlighted by the visit of the HMS Enterprise, a Royal Navy oceanographic survey vessel, to Cork last month.

UK defence officials have become increasingly concerned about the vulnerability of cables passing through the Irish EEZ in recent years, particularly a group of cables that converge about 250km southwest of Cork.

The vulnerability was highlighted in the recent Commission on the Defence Forces report, which said the upgrading of the Naval Service to a nine-ship fleet should involve “the enhancement subsurface capabilities to monitor subsea cables”.

“The fleet’s subsurface capabilities should allow the Naval Service to monitor activity in the vicinity of subsea cables. The fleet should also be equipped with weapon systems capable of deterring aggressive acts against the State, or its infrastructure, in the maritime domain and have mine counter measure capabilities to detect and destroy sea mines.”

Earlier this month, the Government published an action plan based on the report’s findings, which commits to significantly upgrading the Irish Naval Service fleet by the 2030s. However, it is not clear if this will include subsurface capabilities. The department said while the need for subsea cable security is included in the body of the commission’s report, it is not specifically included in its list of 130 recommendations.

Conor Gallagher

Conor Gallagher

Conor Gallagher is Crime and Security Correspondent of The Irish Times