Poland and Britain pledged to provide mutual assistance, including military support, in the event of an armed attack on either country, under a new security and defence partnership treaty signed by Polish Prime Minister Donald Tusk and British Prime Minister Keir Starmer on May 27.

The treaty commits Warsaw and London to deepening defence cooperation, supporting each other’s defence industries and fulfilling their obligations as NATO allies. The two governments said Russia remained a threat to international peace and security, reaffirmed their support for Ukraine and pledged to strengthen deterrence on NATO’s eastern flank.

“The goal of Poland and the United Kingdom is to effectively deter a potential aggressor – Russia. There is no greater challenge for us than Russian aggression. We see this not only in Ukraine itself but also beyond its borders,” Starmer said in a statement.

The Polish-British treaty is also intended to strengthen cooperation within NATO, Tusk said.
According to the treaty, this is expected to happen by maximising the capabilities of the Forward Land Forces to provide credible deterrence on NATO’s Eastern Flank.

“We are doing this to strengthen NATO. We want to be more practical and quicker to respond, should the need arise. The political essence of the agreement is to strengthen European solidarity and transatlantic ties,” Tusk said.

The countries will also create a task force to counter hostile drone use “in particular in view of technological advances and lessons from the use of drones in the war in Ukraine.”

“Building on a strong bilateral partnership in the fields of air defence and advanced weapons systems, Poland and the United Kingdom will together become European leaders in the production and development of the next generation of missile weapons,” the treaty said.

“Poland and the United Kingdom will jointly increase their capabilities in air-to-air weapons, ground-based air defence systems and land capabilities,” it also said.

The agreement also covers internal security threats, including cross-border organised crime, critical infrastructure protection, illegal migration, cyber threats, sabotage, and the hostile use of artificial intelligence and drones.

It also sets out plans for closer cooperation on trade, science, technology, energy security, climate neutrality by 2050, nuclear power and renewable energy.

“The parties uphold the importance of civil nuclear energy in their future energy mixes. They undertake to support nuclear energy as a clean source of energy and to promote access to financing for the development of nuclear projects in Europe and around the world,” the treaty said.

Poland and Britain also pledged to limit Russia’s role in nuclear sector supply chains.

The commitments will be reviewed and assessed, with the heads of both governments due to hold consultations every two years. The treaty must be ratified in both countries before entering into force.