UK-Poland Security Treaty Marks a New Era of Cooperation

On Sunday, 27 May 2026, Prime Minister Keir Starmer met Polish Prime Minister Donald Tusk at RAF Northolt, London, to formalise a new defence treaty between the United Kingdom and Poland. The meeting followed Starmer’s public warning that Russia’s aggression could threaten both nations beyond Ukraine.

During the ceremony, the prime ministers laid a commemorative wreath at the nearby Battle of Britain bunker, symbolising their shared historical commitment to defence and the rule of law. Starmer described the treaty as a "generational uplift" in the security relationship with Poland, stressing that the partnership is built on common values that remain essential for both countries.

The agreement’s agenda is extensive. It seeks to:

1. Support and expand defence jobs in both countries.
2. Enhance cooperation in countering cyber‑attacks and improving border security.
3. Combat organised crime and dismantle criminal networks.
4. Develop a joint action plan to tackle irregular migration through targeted social‑media measures, intelligence sharing and border‑monitoring technologies.

Only a handful of experts have expressed scepticism. Defence adviser Ed Arnold of the RUSI thinks the treaty may not bring many new security measures beyond existing agreements, pointing out that similar accords were signed in 2018 and 2023. According to Arnold, the new treaty focuses more on migration and related security issues than on defence itself, which could introduce risks if policy areas diverge.

Despite these concerns, the treaty reaffirms both nations’ commitment to NATO and recognises Russia as a “significant long‑term threat” to Euro‑Atlantic security. Both leaders emphasised the need for a joint response to the threats posed by Russian aggression, which could endanger not only Ukraine but also their own territories.

In a context where NATO’s eastern flank is perceived as increasingly vulnerable, the treaty is part of broader efforts to strengthen deterrence. The UK and Poland’s cooperation may prove essential to counter Russian advances in the Baltic region, where commentators predict a potential invasion by 2030.

While the treaty’s practical impact remains to be seen, it signals a strategic shift for the UK. By aligning closely with a key EU partner, the United Kingdom positions itself to collaborate more effectively on intelligence, cyber‑security and border protection – areas that increasingly define modern defence strategy.

In conclusion, the 2026 UK‑Poland treaty represents a significant step toward solidifying trans‑Atlantic security ties. Whether it brings measured improvements remains to be proven, but the signing underscores a shared determination to face Russian aggression amid a rapidly evolving geopolitical landscape.