On May 27, 2026, Prime Minister Donald Tusk and Prime Minister Keir Starmer signed a Treaty between the Republic of Poland and the United Kingdom of Great Britain and Northern Ireland on the Partnership in Security and Defence. It is referred to as "the greatest step forward from generation" in bilateral relations.
The Treaty deepens existing cooperation (e.g. from 2017 and 2023) and covers a wide range of: interoperability of armed forces, joint exercises and training, development of defence technologies (including drones and air defense), cybersecurity, combating hybrid threats, exchange of intelligence and cooperation in the defence industry and energy security.
The Parties undertook to consult and coordinate each other in the event of a crisis and reaffirmed their determination to implement Article 5 of the North Atlantic Treaty (the NATO collective defence).
What does this mean for Poland?
For Poland the treaty is primarily additional bilateral security guarantees Next to NATO membership. Britain is one of the most militaryly powerful countries in Europe and a key ally on the eastern flank of NATO. The agreement is intended to accelerate a joint response to threats (especially from Russia), facilitate joint purchases of equipment, exchange of technology and major exercises.
Prime Minister Tusk stressed that history teaches that Poland must build its own defence capabilities and supplement them with strong bilateral alliances.
Are we facing a 1939 replay?
This question arises naturally in the Polish public debate. In September 1939, Poland had alliance treaties with the United Kingdom and France, which however did not translate into real, effective military aid after Nazi Germany and the USSR aggression. The UK and France are limited mainly to declarations and symbolic actions.
But today's context is very different:
- Poland is a member NATO with binding Article 5,
- Britain has much greater power projection capacity than in 1939,
- The Treaty contains specific mechanisms for consultation and operational cooperation,
- The current threat (Russia) is seen as common to all NATO.
Nevertheless, many commentators point out that no treaty is worth more than the real readiness and military capabilities of the parties. The final value of this agreement will only verify the possible crisis.
The treaty is seen as an important deterrent to Russia and strengthening the eastern flank of NATO.
Source: KPRM
