What is the Joint Expeditionary Force?

What and who is the JEF?

The Joint Expeditionary Force (JEF) was established in 2014 at the NATO Summit in Wales by the UK and six other countries. Announcing its formation, the UK government described it as “a pool of high readiness, adaptable forces that is designed to enhance the UK’s ability to respond rapidly, anywhere in the world, with like-minded allies, or on behalf of international organisations such as the UN or NATO.”

Not part of NATO

The JEF is not part of NATO but it does intend to complement it. At a summit in October 2023 JEF leaders outlined this relationship as follows:

For all JEF Participant Nations, NATO is the foundation of collective security in the Euro-Atlantic area. The JEF, from its inception, has been designed to complement both NATO and Participant Nations’ own response capabilities. The JEF needs to be ready to respond in scenarios ranging from below the threshold of NATO's Article 5 through to full-spectrum interventions during times of crisis or conflict, operating seamlessly with NATO.

A former Standing Joint Force Commander, Major General Jim Morris, described how “what the JEF usually does is provide a gearing in-between nations and NATO, where we can discuss issues regionally, we can react to situations on a non-consensus basis, so quickly.”

A 2021 blog post by UK Strategic Command highlighted the flexibility and potential speed of decision making and deployment as some of the advantages of the JEF. Strategic Command also pointed to the potential for JEF allies to “take collective action below the traditional threshold of war”, which it said NATO might not be able to do.

Membership

The JEF is UK-led and was initially made up of six other countries, Denmark, Estonia, Latvia, Lithuania, the Netherlands, and Norway, with the primary goal of protecting northern Europe. Finland and Sweden joined the JEF in 2017 and most recently Iceland joined in 2021, bringing the current total of JEF nations to ten. The addition of then non-NATO members Finland and Sweden meant that the JEF had a broader reach across northern Europe. Finland and Sweden have subsequently joined NATO in 2023 and 2024 respectively.

UK operational lead

The UK is the “framework” or lead nation of the alliance. UK operational command of the JEF is led by Standing Joint Force Headquarters (SJFHQ) in London. Information on JEF activities are provided by SJFHQ on the Joint Expeditionary Force website.

What does the JEF do?

The JEF is not a separate army or fighting force. Rather, it is a collection of units who train and exercise together. It also provides a forum for discussion of defence and security issues between allies. There is an “opt-in” approach which means that as long as two or more JEF members agree to work together, then an exercise can go ahead, with subsequent agreement of the practicalities. The JEF’s geographic focus is the High North, North Atlantic and the Baltic Sea region.

Recent government reviews of defence, security and foreign policy have described Russia as the “the most acute threat” to UK security. The JEF vision (PDF), agreed by leaders of JEF nations in October 2023, stated that Russia’s invasion of Ukraine has increased the importance of JEF as “enablers of regional security” for its members.

Military exercises

In 2019 nine JEF nations took part in Baltic protector, the JEF’s first training deployment. The exercise included a total of 20 ships and around 3,000 personnel, culminating in practice amphibious landings in Europe’s Baltic states.

In October 2023 then Prime Minister Rishi Sunak promised to “step up” the UK’s presence in northern Europe, committing to sending more than 20,000 service personnel to the region in 2024 on exercises, training and operational deployments.

JEF exercises have also been coordinated with NATO exercises. For example, in February 2024 a JEF air defence exercise, global guardian, was coordinated with NATO’s steadfast defender exercise.

The UK’s SJFHQ has hinted that exercises are held with Russia in mind. In a press release on global guardian in 2024, they highlighted how such exercises “are important for sending a clear message that deter malign activity and reassure friends.”

During 2023 the JEF has developed a series of what it has described as Response Options, which it said are “designed to deter, and defend our region from threats and establish how quickly we can respond to crises.”

Defending critical national infrastructure

In October 2023 JEF leaders agreed at a summit held in Sweden to deepen cooperation on protecting critical national infrastructure. Critical national infrastructure includes undersea communication cables and energy pipelines; in 2022 the Nord Stream pipelines in the Baltic Sea were sabotaged, highlighting the potential vulnerability of undersea cables and pipelines to malicious attack.

In November 2023, the JEF Defence Ministers agreed to activate for the first time a JEF response option, enabling the deployment of maritime and air capabilities to help protect critical undersea infrastructure across the JEF’s core region.

A second response option took place throughout June 2024, monitoring shipping, undersea energy and communication routes, and suspicious activity. It was led from SJFHQ in London, using a total of 28 ships and 6 aircraft from JEF nations.

Ukraine observers

In October 2023 JEF leaders agreed to invite Ukraine to observe JEF exercises during 2024 and 2025. Their presence is intended to “increase interoperability, and enhance the capability of the Armed Forces of Ukraine”.

Boris Johnson, when Prime Minister, noted similarities in thinking among JEF allies, noting that the JEF “consists of the countries that were fastest off the block, with us, in sending direct military assistance to Ukraine”.

What does the future of the JEF look like?

In its election manifesto 2024, the Labour party said that the “first duty in government will be to keep our country safe”. As part of this they stated that they would pursue “new bilateral agreements and closer working with Joint Expeditionary Force partners.”

The government has launched a strategic defence review to “consider the threats Britain faces, the capabilities needed to meet them, the state of UK armed forces and the resources available”, to report in the first half of 2025.

In the 2023 Defence Command Paper (PDF), the Conservative government said that it would “continue to prioritise our leadership of both the JEF and the Northern Group, promoting ongoing close cooperation and interoperability”.

In February 2023, the Defence Select Committee reported that “the UK’s focus on the High North [the Arctic and parts of the North Atlantic] and its leadership within the Joint Expeditionary Force are to be commended.”

Commentators have considered how the JEF can grow and adapt. Lord Peach, a former Chief of the Defence Staff, Brigadier Robbie Boyd, a former Vice Chief of the Defence Staff, and RUSI research fellow Ed Arnold, have argued that “with political momentum behind the JEF, now is the right time to deepen cooperation within the framework.” They argue that development such as a “JEF Bank” and “JEF Digital” would expand and develop the forces capabilities and importance. They depict the former as a “dedicated investment bank for defence capability, or a technology venture capital fund” and the latter as enhancing the UK’s digital transformation and modernisation, such as secure networks, with Scandinavia’s digital technology industries.