NORTHOLT, United Kingdom — May 27, 2026 : The United Kingdom and Poland signed the Northolt Treaty on Wednesday at RAF Northolt air base in west London, formalising a new bilateral defence and security agreement aimed at expanding military cooperation, defence industrial collaboration and regional security coordination between the two NATO allies.
British Prime Minister Keir Starmer and Polish Prime Minister Donald Tusk signed the agreement during a ceremony at RAF Northolt, a site with historical significance as the base from which Polish pilots operated during the Second World War and where a memorial to them remains.
The Northolt Treaty establishes a framework for closer defence and security cooperation, including the joint development and production of next-generation military systems. Key areas identified in the agreement include missile defence systems, medium-range missiles and drone technologies. The pact also provides for the co-production of a next-generation medium-range air defence missile by combining industrial expertise and manufacturing capabilities in both countries.
A central pillar of the agreement is the expansion of military interoperability between British and Polish forces through large-scale joint exercises. These exercises are expected to focus on counter-drone warfare, electronic warfare, advanced missile defence operations and engineering support, while also improving operational coordination between both militaries.
The treaty further strengthens defence industrial cooperation by promoting closer coordination between defence manufacturers, industrial planning and export strategies to secure supply chains and support long-term production requirements. The agreement also aims to deepen collaboration between domestic defence sectors in both countries.
Security cooperation under the treaty extends beyond conventional military matters. The agreement includes measures to counter hybrid threats such as cyber attacks, disinformation campaigns and hostile influence operations, while also covering border security, cybersecurity resilience and efforts to combat organised crime.
The treaty explicitly identifies Russia as the most significant long-term threat to Euro-Atlantic security and outlines measures intended to improve deterrence and strengthen regional security, particularly across Eastern Europe. It includes a mutual assistance commitment under which both countries agreed to support one another in the event of an armed attack, while aligning these obligations with Article 5 of the North Atlantic Treaty Organization.
British and Polish leaders emphasised that the agreement is intended to complement, rather than replace, NATO commitments. Tusk said the treaty would strengthen Polish and British security, protect cyberspace and reinforce NATO as a whole. He stated that the agreement transforms political partnerships into practical measures intended to address security threats before they escalate, while reinforcing shared democratic principles, the rule of law and human rights.
Starmer described the Northolt Treaty as the biggest step forward in the UK’s defence and security relationship with Poland in a generation, stating that the agreement would strengthen joint capabilities, deepen bilateral cooperation and enable both countries to address modern security challenges while jointly developing and manufacturing advanced military systems.
The agreement builds upon the 2017 UK–Poland Treaty on Defence and Security Cooperation and expands an already growing defence relationship between the two countries. In 2024, Poland signed a £4 billion procurement agreement for more than 1,000 CAMM-ER surface-to-air missiles and launchers from European missile manufacturer MBDA. Poland’s state-owned defence group Polska Grupa Zbrojeniowa also entered a strategic partnership with BAE Systems to support production of 155mm artillery shells.
The Northolt Treaty follows similar bilateral defence agreements recently signed between the United Kingdom, France and Germany, while Poland also concluded a defence treaty with France in 2025. These agreements reflect broader efforts among several European military powers to strengthen defence cooperation, industrial coordination and regional security planning.
No information regarding the treaty’s duration or specific financial commitments linked to the agreement was disclosed at the time of signing.
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