Britain and nine European partners are developing a new multinational maritime force under the UK-led Joint Expeditionary Force, as concern grows over Russian naval activity in the North Atlantic, the High North and the Baltic Sea.

Britain and nine European partners have agreed to develop a new multinational maritime force intended to strengthen deterrence against Russia in the High North, the North Atlantic and the Baltic Sea.

The initiative was announced by General Sir Gwyn Jenkins, the First Sea Lord and head of the Royal Navy, who said members of the UK-led Joint Expeditionary Force had signed a statement of intent to create a force that would complement NATO rather than replace it. The proposed formation would bring together the United Kingdom, the Netherlands, Denmark, Finland, Iceland, Norway, Sweden, Estonia, Latvia and Lithuania. Canada is also reported to be considering participation, according to The Guardian.

The move reflects growing concern in London and among northern European capitals over Russian naval activity, including surface deployments, submarine operations and suspected probing of undersea infrastructure. In a speech at the Royal United Services Institute, Jenkins said Russian incursions into UK waters had risen by almost a third over the past two years, adding that the Royal Navy had been required to respond dozens of times in 2025 in support of homeland defence.

Although the crisis in the Middle East and disruption in the Strait of Hormuz have placed additional pressure on Western navies, Jenkins said Russia remained the most serious threat to Britain’s security. He described the UK as having an “open sea border” with Russia to the north, a reference to the maritime approaches linking the North Atlantic, Arctic waters and the strategically important routes used by Russian naval forces.

The Joint Expeditionary Force was established in 2014 and has since developed as a UK-led military partnership focused largely on northern Europe. Its members include the Baltic states, the Nordic countries and the Netherlands. A JEF statement said the latest naval chiefs’ meeting was aimed at reinforcing deterrence in the North Atlantic and Baltic region.

According to British officials, the proposed maritime force would train, exercise and prepare together, with command available, if necessary, from the UK’s military headquarters at Northwood, north-west London. The ambition is to create a formation with shared planning, common procedures and integrated capabilities rather than a loose framework for occasional deployments. Jenkins said the force should be “designed to fight immediately if required”, with real capabilities, war plans and integration.

The initiative also has an industrial and technological dimension. Britain is seeking closer naval integration with allies through common platforms, shared logistics, digital networks and stockpiles. The Royal Navy has pointed to the programme, already involving exports to Norway and Canada, as a possible basis for deeper fleet compatibility among allied navies, according to a Royal Navy account of the discussions.

However, the announcement comes amid continuing scrutiny of Britain’s naval readiness. Reports have cited concerns over ship availability, maintenance delays and the long-term effects of earlier reductions in investment. Jenkins has acknowledged that the Royal Navy must adapt more quickly, arguing that it cannot meet future threats by relying only on traditional crewed warships.

A central part of the proposed transformation is the development of what Jenkins has called a “Hybrid Navy”. This would combine conventional ships and submarines with autonomous and uncrewed systems, including large uncrewed escort vessels expected to operate alongside British warships within the next two years. The Royal Navy is also developing the Atlantic Bastion programme, a layered sensor network intended to help detect and respond to hostile subsurface activity in the North Atlantic.

For European security, the planned force marks a further shift towards regional groupings operating inside the wider NATO framework. The JEF’s geography gives it a particular role in areas where Russian activity is most visible: the Baltic Sea, the North Sea, the Norwegian Sea and the approaches to the Arctic. These are also regions where energy infrastructure, data cables and shipping lanes are vulnerable to disruption.

The new maritime force is not intended to alter NATO command structures, but to provide a more agile mechanism for rapid action before or alongside Alliance-level decisions. That could make it particularly relevant in situations below the threshold of full collective defence, including surveillance of Russian vessels, protection of infrastructure and coordinated responses to suspected hybrid activity.

The success of the project will depend on whether political intent is matched by ships, crews, logistics and sustained investment. The strategic rationale is clear: Russia’s northern and underwater activity has become a continuing concern for Britain and its closest European partners. The operational challenge will be to turn a statement of intent into a standing maritime capability able to deter, respond and, if required, fight from the first hours of a crisis.