Publication date: November 04, 2026
On 4 November 2026 the Polish statute of 18 September 2026 consenting to the ratification of the Treaty between the Republic of Poland and the United Kingdom on a Security and Defence Partnership, known as the Northolt Treaty, was signed. The remaining steps are ratification and the exchange of notifications between Warsaw and London; the Treaty enters into force 30 days after the later notification.
For defence companies, the headline is not only the bilateral mutual assistance clause. The Treaty commits both governments to align defence-industrial and export strategies, procure jointly, remove regulatory barriers to joint programmes and secure supply chains. The first implementing instrument, the Warsaw Defence Plan of 27 October 2026, already names concrete programmes: next-generation air defence missiles, large-calibre ammunition, drones and counter-drone systems, and the Miecznik frigates.
The Treaty was signed by Prime Ministers Donald Tusk and Keir Starmer on 27 May 2026 at RAF Northolt, the wartime base of the Polish 303 Squadron. It has 12 articles and builds on the 2017 UK-Poland Treaty on Defence and Security Cooperation and the 2023 Joint Declaration on the 2030 Strategic Partnership.
| Article | Subject | Key point for industry |
| 1 | Foreign and security policy | Coordinated sanctions policy; use of the EU-UK Security and Defence Partnership of 19 May 2025 |
| 2 | Defence and security | Mutual assistance clause; joint procurement; aligned industrial and export strategies; R&D and technology transfer |
| 3 | National security | Hybrid threats, sabotage, hostile drones, FIMI, critical infrastructure, organised crime, migrant smuggling |
| 4 | Economic security | Supply chain resilience, dual-use transport infrastructure, investment dialogue, research security |
| 5 | Energy and climate security | Protection of offshore energy infrastructure; civil nuclear; reducing Russian inputs in nuclear supply chains |
| 6 | Governance | Senior officials’ coordination mechanism; prime ministers review implementation every two years |
| 7-12 | Final clauses | Executed under national law; disputes by negotiation only; six months’ notice of termination; entry into force 30 days after the later notification |
Article 8 allows the Treaty to be extended to Guernsey, Jersey and the Isle of Man by an exchange of notes.
Poland ratifies with prior consent given by statute, because the Treaty is a political and military alliance under Article 89(1)(1) of the Constitution and touches matters reserved to statute under Article 89(1)(5). The ratification statute has two articles: consent to ratification, and entry into force on the day after publication. The government shortened the vacatio legis to speed up implementation.
| Date | Step |
| 4 Nov 2026 | Ratification statute signed; ratification and exchange of notifications to follow |
| 27 Oct 2026 | Defence ministers sign the Warsaw Defence Plan, the first implementing plan |
| 18 Sep 2026 | Sejm adopts the ratification statute |
| 22 Jul 2026 | Government bill submitted to the Sejm (print no. 2840) |
| 23 Jun 2026 | UK government lays the Treaty before Parliament (Command Paper CS Poland No. 1/2026) under the CRaG Act 2010 |
| 27 May 2026 | Treaty signed at RAF Northolt; 14 landmark projects published |
The UK Command Paper dates the Treaty “London, 26 May 2026”, while Polish documents use 27 May, the date of the signing ceremony. At the time of writing we have not seen confirmation that either party has deposited its notification, so the Treaty is not yet in force.
Under Article 2(5), if either party suffers an armed attack, the other commits to provide assistance, including by military means, in accordance with Article 5 of the North Atlantic Treaty. The clause adds a bilateral layer to NATO collective defence rather than replacing it, mirroring the treaties the UK signed with France and Germany and Poland’s 2025 Nancy Treaty with France.
Article 2 also commits both states to:
Article 2(6) is the provision defence companies should read first. Recognising the value of security of supply for national programmes and a reliable order pipeline for defence firms, the parties commit to:
On signature the governments published 14 priority projects. Those most relevant to industry are below, together with how the Warsaw Defence Plan of 27 October 2026 (the first phase of defence cooperation under the Treaty) takes them forward.
| Area | Treaty landmark project (May 2026) | Warsaw Defence Plan (Oct 2026) |
| Complex weapons | Joint development and manufacture of next-generation missiles across air-to-air, ground-based air defence and land | Next-generation air defence missiles; builds on Poland’s Narew procurement from MBDA UK |
| Defence industry | Coordinated procurement, workforce mobility, support for third-country exports, technology transfer | Closer procurement coordination; education, training and workforce mobility |
| Ammunition | Expanded large-calibre production, with government-enabled knowledge and technology transfer | BAE Systems and PGZ to expand large-calibre ammunition capacity |
| Land and eastern flank | Strategic Land Partnership; exercises on counter-drone, EW and missile defence | Steadfast Defender, Polish Dragon, Joint Warrior; drone and counter-drone co-development |
| Maritime | North Sea and Baltic security; joint training for next-generation frigate crews; air defence missile procurement | Lessons shared between Type 31 and Miecznik (common design); more Baltic activity |
| Cyber | Military defensive cyber and civilian cyber deterrence | Cyber security and resilience of defence and civilian sites |
| Counter-drone (civil) | Joint task force developing detection and mitigation tools | Covered by drone and counter-drone line above |
Other landmark projects cover sanctions coordination, a counter-hybrid cooperation agreement and working group, FIMI, irregular migration, science and technology (quantum, space), health security (including CBRN and medical evacuation), energy security and diplomatic exchanges.
The Polish government describes the Treaty as political in character. According to the explanatory memorandum, it concerns cooperation between state authorities and does not directly affect natural or legal persons, does not directly regulate matters governed by domestic law, and requires no implementing legislation. The Ministry for EU Affairs confirmed that it is compatible with EU law.
The Treaty creates no direct financial obligations. Any costs for the Ministry of National Defence will be met within the defence spending limit under Article 40 of the Homeland Defence Act of 11 March 2022, without additional budget requests.
In practice, this means that nothing changes overnight in procurement law, export control or security clearance rules. The opportunities will come through the implementing instruments: defence cooperation plans such as the Warsaw Defence Plan, programme-level agreements, and the project pipeline reviewed under the Article 6 governance mechanism. Existing instruments remain the operative legal base, notably the 2017 Treaty and the 2006 UK-Poland Agreement on the Mutual Protection of Classified Information (amended in 2017).
Once notifications are exchanged, the Treaty will sit alongside Poland’s treaty with France and its planned agreement with Germany as a pillar of Warsaw’s bilateral security network inside NATO. The near-term signals to watch are the first biennial prime ministerial review under Article 6, new programme agreements under the Warsaw Defence Plan, and any new agreements on military mobility or the transfer of prisoners announced under Articles 2 and 3.
KG Legal advises Polish and foreign clients on corporate and M&A transactions, EU regulatory matters and cross-border disputes. If you are planning a UK-Polish teaming arrangement, a joint venture or an investment in the Polish defence sector, contact KG LEGAL KIELTYKA GLADKOWSKI at office@kg-legal.pl.
This article is for general information only and is not legal advice.