Poland and UK Sign Landmark Defence Treaty as President Nawrocki Decries Lack of Consultation

A historic agreement in a symbolic setting

Poland and the United Kingdom signed a new Treaty on Partnership in Security and Defence on Wednesday, 27 May 2026. The document was signed by Prime Minister Donald Tusk and Prime Minister Keir Starmer at a museum dedicated to the Battle of Britain in Uxbridge, west London, a site that also commemorates the Polish pilots who fought in the conflict. Both leaders described the treaty as a historic, generation-defining upgrade to bilateral relations.

We have a long shared history together, we share similar values, we fought together and we also face similar challenges today.

The treaty commits both nations to mutual assistance, including the use of military means, in the event of an armed attack on either party, in accordance with Article 5 of the North Atlantic Treaty. It explicitly names Russia as a threat to international peace and security and reaffirms support for Ukraine.

Scope of cooperation

The agreement covers a broad range of security domains. It includes joint military training, intelligence sharing, cybersecurity cooperation, and the development of defence industries. The two countries plan to co-produce advanced new-generation medium-range air defence missiles and strengthen anti-missile systems. The treaty also addresses combating hybrid threats, disinformation, illegal migration, and the protection of critical infrastructure such as maritime, energy, and health systems.

First, what do we want to defend? We want to defend a secure United Kingdom and Northern Ireland. We want to defend a secure Poland, our territories, our borders. Second, we want to protect cyberspace, because modern technologies mean that no one feels safe today and cooperation in this area is so crucial.

Tusk added that the political essence of the treaty is to strengthen European solidarity, solidarity within NATO, and Euro-American solidarity.

Presidential pushback from Switzerland

President Karol Nawrocki, who was on a visit to Switzerland and meeting with members of the Swiss Federal Council in Bern, was asked at a press conference whether he intends to ratify the treaty. He revealed that until the previous day, he had only learned about the agreement from public sources.

As for the signing of the Polish-British agreement, until yesterday I obtained information on this matter exclusively from public opinion as the President of Poland, but thanks to the great courtesy and professionalism of one of the deputy ministers, we received information about the signing of the Polish-British cooperation document yesterday.

Nawrocki stated that he would thoroughly examine the document before making any decision on ratification, and suggested that the Presidential Chancellery should be informed before such commitments are made on behalf of the Polish nation.

Government fires back

The head of the International Policy Bureau, Marcin Przydacz, confirmed that the government had not consulted the presidential office on the treaty, adding that he often received broader information from the British side about the negotiations. Deputy Prime Minister and Defence Minister Władysław Kosiniak-Kamysz, speaking from a defence expo in Ottawa, Canada, reacted sharply.

I would like the presidential chancellery to be happy for once that Poland is safer. It drives a man mad to constantly hear only about the presidential chancellery's own backyard. It is not the centre of the world.

Kosiniak-Kamysz also referenced a past incident where the president did not sign the SAFE programme, suggesting he now regrets not being part of the team modernising the Polish armed forces. The treaty must undergo ratification procedures in both countries before it can enter into force.