UK-Ukraine 100-year partnership agreement: House of Lords International Agreements Committee report

Approximate read time: 20 minutes

On 22 April 2025, the House of Lords is scheduled to debate the International Agreements Committee’s report ‘UK-Ukraine 100 Year Partnership Agreement’ (26 March 2025, HL Paper 102 of session 2024–25).

1. One Hundred Year Partnership Agreement

During a visit to Ukraine, Prime Minister Sir Keir Starmer signed a ‘One Hundred Year Partnership Agreement’ with Ukraine on 16 January 2025.^[1] The government said the agreement would formalise “the unbreakable bonds between the UK and Ukraine”, by “broadening and deepening the relationship across defence and non-military areas and enabling closer community links”.^[2] The government expected the agreement to “bolster military collaboration on maritime security through a new framework to strengthen Baltic Sea, Black Sea and Azov Sea security and deter Russian aggression”.

The government has described the agreement as establishing “a legal framework governing cooperation and partnership between the UK and Ukraine, setting out the key principles governing the 100YP [100-year partnership] and outlining the thematic areas for cooperation”.^[3] The agreement contains provisions setting out obligations to cooperate in the following areas:

• strengthening defence capabilities
• strengthening security and building consensus on Ukraine’s NATO membership
• building a partnership in the field of maritime security
• increasing economic and trade cooperation
• strengthening energy, climate, and clean energy transition cooperation
• increasing justice and accountability cooperation
• combating foreign information manipulation and interference
• boosting positions as leaders in science, technology and innovation
• harnessing socio-cultural ties
• migration cooperation

The agreement provides that it will remain in force for 100 years from its entry into force, although it could be terminated by either party with six months’ written notice.

Alongside the agreement, Sir Keir and Ukrainian President Volodymyr Zelensky also signed a non-legally binding ‘UK-Ukraine 100 year partnership declaration’.^[4] This sets out more detail on cooperation across nine ‘pillars’ that correspond to the policy areas included in the agreement (there is no dedicated migration pillar in the declaration, but migration is covered in the social, culture and sport pillar). The duration of the declaration is also 100 years, and it also could be terminated by either side with six months’ written notice.

On defence and security, the agreement provides that the UK and Ukraine will:^[5]

[…] deepen defence cooperation, strengthen their military and defence industrial capabilities, including force development and collaboration between their defence industrial bases, strengthen Ukraine’s defence procurement, and transfer technologies for joint production of defence products (including through joint initiatives).

It commits them to “build[ing] on areas that benefit Euro-Atlantic peace and stability well beyond the war” and states that this will be “with a focus on Ukraine’s inter-operability and contribution as a future NATO ally”. The agreement states that the UK and Ukraine “shall endeavour to address long-term systemic threats and challenges to maritime security in order to restore freedom of navigation”. It also commits them to establishing a maritime security partnership, an objective of which will be strengthening Black Sea, Baltic Sea and Azov Sea security.

The non-legally binding declaration provides examples of how the partners intend to deepen defence cooperation, such as carrying out joint defence capability projects and cooperating in creating “flexible rapid response mechanisms” including “joint use of military formations and other specialised structures to provide a wide range of mutual defence and security services”. The declaration states that the UK will provide Ukraine with annual military assistance of no less than £3bn a year until 2030/31 and “for as long as needed to support Ukraine”. Sir Keir Starmer pledged this financial support to Ukraine shortly after taking office in July 2024.^[6]

On security, the declaration states that “neither participant will be left alone in the face of an attack or aggression”. If either side is attacked in violation of the UN charter and fundamental principles of international law, both sides would consult within 24 hours “to determine the measures needed to counter or deter aggression”. Each side “acting in accordance with its legal requirements will provide each other swift and sustained security assistance, modern military equipment as necessary, and economic assistance”. The declaration says that the maritime partnership will focus on “speedy restoration of Ukraine’s control over all temporarily occupied territories” The Ukrainian Navy and Royal Navy will deepen operational cooperation, including operating in joint task groupings (‘flotillas’) where appropriate.

The government believes that the agreement will benefit the UK in several ways:^[7]

• security benefits arising from closer military and defence cooperation, improved border management engagement and countering disinformation activity
• ongoing economic, climate and scientific dividends from closer trade, investment, energy and innovation cooperation
• societal and cultural advantages flowing from increased partnerships in these areas spanning the arts, sport, youth exchange and migration

Speaking about the agreement in the House of Commons, Foreign Secretary David Lammy argued that supporting Ukraine was “not simply a moral necessity”, but also “a strategic necessity for Britain and our allies”.^[8] He said that if Russia were to win in Ukraine, “the post-war order […] which has kept us all safe for more than eight decades will be seriously undermined” and “foundational principles of sovereignty and territorial integrity will be shaken”.

The One Hundred Year Partnership Agreement builds on earlier agreements between the UK and Ukraine. Prime Minister Rishi Sunak and President Zelensky signed a 10-year UK-Ukraine ‘Agreement on Security Cooperation’ in January 2024. The Conservative government described the security cooperation agreement as “the first step in developing an unshakeable hundred-year partnership between Ukraine and the United Kingdom”.^[9]

Both agreements also build on the UK-Ukraine ‘Political, Free Trade and Strategic Partnership Agreement’ signed in October 2020 which provided a framework for political, foreign and security policy cooperation and a preferential trade agreement following the UK’s exit from the EU.^[10]

2. House of Lords International Agreements Committee report

2.1 Key findings

The House of Lords International Agreements Committee published its report on the One Hundred Year Partnership Agreement on 26 March 2025.^[11] The committee declared it “support[ed] the underlying rationale for the agreement and welcome[d] the UK’s support for Ukraine”, which “could contribute to Ukraine’s ability to deter future aggression”.^[12] However, it noted that the obligations in the agreement were “expressed in very general and aspirational terms”.^[13] It concluded that “the value of this agreement appears to lie primarily in its signalling function”.^[14] It also suggested that the title of the agreement was “rather meaningless, and risks distracting attention from the substance of the partnership”. At the same time, the committee was “concerned by the lack of detail on the substance of the agreement”. It suggested that for any benefits from the agreement to be realised, “a clear and realistic roadmap will have to be put in place”, but this was “currently lacking”.^[15]

The committee observed that there was “insufficient detail” in the agreement and accompanying declaration to allow it to understand how benefits to the UK might be realised from defence cooperation with Ukraine.^[16] It welcomed additional evidence from Stephen Doughty, minister of state for Europe, North America and UK overseas territories, that provided further detail on commercial opportunities for UK businesses in defence and other sectors.^[17] However, it asked the government for more information, including timelines, about how the activities outlined in pillars 1 and 2 of the declaration (namely defence and security) would be undertaken, and for “reassurance as to what benefit they will provide the UK”.

The committee also considered the question of security guarantees for Ukraine, noting that this “became still more prominent in early 2025, when the US initiated peace talks in an attempt to bring the Russia-Ukraine conflict to an end”.^[18] The committee said there was “broad agreement” among its witnesses that the One Hundred Year Partnership Agreement on its own “does not offer a deterrent” to Russian aggression.^[19] It highlighted evidence from Stephen Doughty that although the agreement was “distinct” from ongoing discussions about an immediate package of security guarantees for Ukraine, its “locks into” those discussions “very neatly”.^[20] The committee welcomed the government’s aim that “the agreement, alongside other measures, should offer a framework to build an effective deterrence to future Russian aggression”.^[21] It recommended that if some sort of agreement is reached between Ukraine and Russia, the government should undertake a formal review of the agreement and declaration to ensure they were “appropriate to, and compatible with, any outcome”. It suggested the government should keep the agreement under review in any case, to ensure it was “utilised in an effective, resource efficient manner, while also keeping in mind risks to the UK”.

Similarly, on the maritime partnership specifically, the committee called for more detail about what additional support the UK would offer to Ukraine and how this would build on existing maritime cooperation.^[22] It concluded that proceeding with the maritime security partnership should be subject to appropriate risk assessments and “any maritime and naval support should contribute to the overall security of the region”.^[23] The committee called for the maritime security partnership to be reviewed swiftly in the event of an agreement between Ukraine and Russia, and for Parliament to be informed of any changes to the priorities of the maritime partnership.

The committee encouraged the government to continue to work closely with the Ukrainian government on governance reforms and strengthening the rule of law.^[24] It suggested the government consider structuring aid to Ukraine and cooperation under the 100-year partnership “so as to best promote and strengthen” these areas.

The committee also welcomed the government’s commitment to pursuing accountability for crimes committed during the conflict in Ukraine, in particular through its support for the efforts of the Ukrainian prosecutor general and the International Criminal Court.^[25] It also commended existing cooperation on addressing foreign information manipulation and interference.^[26]

It its conclusions, the committee expressed support for the government’s broad policy on Ukraine. It said it welcomed the government’s “ongoing support for the sovereignty and territorial integrity of Ukraine, its position on security guarantees and a US backstop, and its commitment to future domestic defence spending”.^[27] The committee said these steps would be “vital to achieve successful implementation of the agreement”.

The committee reported the agreement to the House for “special attention and debate, in light of the heightened political interest in events in Ukraine and the UK-Ukraine relationship”.^[28] The government has not yet responded to the committee report.

2.2 Parliamentary scrutiny of the agreement

The House of Lords International Agreements Committee scrutinises all treaties that are laid before Parliament under the terms of the Constitutional Reform and Governance (CRAG) Act 2010 (CRAG Act 2010). Although no debate or vote in either House of Parliament is required prior to a treaty being ratified, under the CRAG Act 2010 treaties are laid before Parliament for 21 sitting days before they can be ratified. The House of Lords can vote against ratification, but the government can still proceed by making a statement setting out why it believes the treaty should be ratified.^[29]

The government laid the agreement before Parliament on 24 February 2025. The 21-sitting day ‘objection period’ was due to end on 28 March 2025. At the International Agreements Committee’s request, the government agreed to extend this scrutiny period to enable the House to debate the committee’s report following the Easter recess.^[30] The objection period is now due to end on 1 May 2025.

3. Recent developments

The committee noted in its report that scrutiny of the agreement is taking place in the context of a “highly uncertain” and “rapidly changing geopolitical environment as regards Ukraine’s future”.^[31]

3.1 US policy

The agreement was signed days before Donald Trump’s inauguration as US president in January 2025. Since he took office, US government policy towards Ukraine has experienced a shift in approach, including direct negotiations with Russia over ending the conflict and increasing pressure on Ukraine to come to the negotiating table, for instance by temporarily suspending US military aid and intelligence sharing. The US has also said it does not see a return to Ukraine’s pre-2014 borders or NATO membership for Ukraine as realistic outcomes of a negotiated settlement.^[32] NATO member states, including the US under President Biden, had previously resolved that Ukraine was on an “irreversible path” towards NATO membership.^[33] The US shift in policy and other recent developments are explored in more detail in the following briefings: House of Lords Library, ‘Recent US and UK government policy on Ukraine’ (12 March 2025); and House of Commons Library, ‘Ukraine and Russia: A shift in US policy’ (3 April 2025).

Despite US-brokered proposals for a ceasefire, the conflict has continued. Ukraine agreed in mid-March 2025 to a US proposal for an interim 30-day ceasefire and to immediately begin negotiations “toward an enduring peace that provides for Ukraine’s long-term security”.^[34] President Putin said that Russia was in favour of a 30-day ceasefire that would “lead to long-term peace and eliminate the root causes of the crisis”, but he effectively imposed conditions on accepting a ceasefire by arguing there were “nuances” and “issues” to be discussed about its purpose and enforcement.^[35] Although President Putin did not commit to a full ceasefire, he did subsequently agree in a phone call with President Trump to a 30-day halt in either side attacking energy infrastructure.^[36] However, there have continued to be attacks on infrastructure and claims by both sides that the other has breached this moratorium.^[37]

Ukraine and Russia both agreed to a naval ceasefire in the Black Sea as a result of separate talks with the US in Riyadh in late March 2025.^[38] Both sides agreed to ensure safe navigation, eliminate the use of force and prevent the use of commercial vehicles for military purposes in the Black Sea.^[39] However, Russia said that the ceasefire in the Black Sea would not take effect unless sanctions against Russian banks and its food and fertiliser trades were lifted.^[40]

US envoy Steve Witkoff met President Putin on 11 April 2025 for talks about “aspects of a Ukrainian settlement”.^[41] President Trump said Russia “has to get moving” as “too many people [are] dying”.^[42] However, a Kremlin spokesperson said that ongoing US-Russian negotiations were unlikely to yield “lightning-fast results”.^[43]

On 13 April 2025, at least 34 people were killed and 117 injured in a Russian ballistic missile attack on the Ukrainian city of Sumy.^[44] The US ambassador to Kyiv, Bridget Brink, said reports indicated that cluster munitions had been used, increasing the devastation and harm to civilians.^[45] Sir Keir Starmer said the attacks were “horrific”.^[46] He said President Zelensky had shown his commitment to peace and indicated that President Putin should do the same, saying he “must now agree to a full and immediate ceasefire without conditions”.

US attempts to bring about a negotiated peace deal have highlighted the question of security guarantees for Ukraine, as the International Affairs Committee highlighted in its report. US Secretary of Defense Pete Hegseth said in February 2025 that any security guarantee for Ukraine “must be backed by capable European and non-European troops”. He made clear that “as part of any security guarantee, there will not be US troops deployed to Ukraine”. He emphasised that “safeguarding European security must be an imperative for European members of NATO” and it must be Europe (and by implication, not the US) that “must provide the overwhelming share of future lethal and non-lethal aid to Ukraine”.^[47] He also said that any peacekeeping troops deployed to Ukraine should not be part of a NATO mission and should not be covered by NATO’s article 5 collective defence provision.^[48]

The US has also suggested that a security guarantee for Ukraine could be economic rather than military. Vice President JD Vance said that “the very best security guarantee is to give Americans an economic upside in the future of Ukraine”.^[49] The US and Ukraine issued a joint statement on 11 March 2025 in which they agreed to “conclude as soon as possible a comprehensive agreement for developing Ukraine’s critical mineral resources to expand Ukraine’s economy and guarantee Ukraine’s long-term prosperity and security”.^[50] Talks on a US-Ukraine critical minerals deal are ongoing. According to press reports, the latest US draft would give the US privileged access to Ukraine’s mineral deposits and require the income from the exploitation of natural resources by Ukrainian state and private firms to be placed in a joint investment fund, but would not provide US security guarantees.^[51]

3.2 UK role in establishing a ‘coalition of the willing’

Sir Keir Starmer has said that a critical minerals deal “is not enough on its own” to provide a security guarantee to Ukraine.^[52] The UK has been playing a leading role in efforts to establish an international ‘coalition of the willing’ to defend any peace deal reached in Ukraine and provide guarantees. The UK convened a meeting in London on 2 March 2025, attended by the leaders of various EU countries and Canada, the Turkish foreign minister, the secretary general of NATO and the presidents of the European Commission and Council of the EU. Sir Keir said leaders had agreed the following points:^[53]

• to keep military aid flowing and increase economic pressure on Russia
• that any lasting peace must ensure Ukraine’s sovereignty and security, and Ukraine must be at the table for negotiations
• to keep boosting Ukraine’s defensive capabilities in the event of a peace deal to deter any future invasion
• to develop a ‘coalition of the willing’ to defend a deal in Ukraine and guarantee the peace

He acknowledged that “not every nation will feel able to contribute”, but those that were would begin to intensify their planning. He said the UK was willing to back this commitment with “boots on the ground, and planes in the air”. He also said that Europe “must do the heavy lifting”, but “to succeed, this effort must have strong US backing”.

During March and April 2025, a series of high-level meetings of leaders and defence chiefs took place to move forward with operational planning to put this four-point plan into action.^[54] Sir Keir Starmer said on 27 March 2025 that partners had offered contributions ranging from logistics and command and control to deployments on land, air and sea.^[55] He said the ‘coalition of the willing’ would be “ready to operationalise a peace deal whatever its precise shape turns out to be”.

The most recent meeting of the ‘coalition of the willing’ took place on 10 April 2025, chaired by Defence Secretary John Healey and his French opposite number Sébastien Lecornu, and attended by ministers from 30 countries and representatives from the European Commission, the Council of the EU and NATO.^[56] A joint UK-French statement said discussions centred on how participating nations could contribute their capabilities to ensure Ukraine’s future security, whether by strengthening Ukraine’s security or by providing direct contributions. The statement said the coalition’s objectives were “to reassure, support and protect Ukraine to ensure that any peace settlement secures against the risk of future Russian aggression”. It said the coalition was making “solid progress” on building a multinational effort, although specific details could not be given until the conditions of a ceasefire were made clear. According to press reporting, Mr Healey outlined four planning objectives at the meeting: securing safe skies, safe seas, peace on land and supporting the Ukrainian armed forces “to become their own strongest possible deterrent”.^[57] He also emphasised that the reassurance mission would not be a peacekeeping force that would separate warring sides.^[58]

In their joint statement, Mr Healey and Mr Lecornu also urged President Putin to sign up to a full and unconditional ceasefire, as Ukraine has done.^[59]

The UK and Germany chaired a meeting of the Ukraine Defence Contact Group on 11 April 2025. The government announced that a military support package worth £450mn would be delivered by Ukrainian and British suppliers to boost the Ukrainian armed forces. £350mn of the funding came from the UK, as part of £4.5bn military support funding for Ukraine the government has said it will provide this year.^[60]

4. Read more

• House of Commons Library, ‘Ukraine and Russia: A shift in US policy’, 3 April 2025
• House of Lords Library, ‘Recent US and UK government policy on Ukraine’, 12 March 2025
• House of Commons Library, ‘Detailed timeline of UK military assistance to Ukraine (February 2022–present)’, 24 March 2025
• House of Lords Library, ‘Ukraine: A wake-up call—Lords committee report debate’, 13 February 2025
• House of Commons Library, ‘UK-Ukraine 100-year partnership agreement’, 5 February 2025
• House of Commons Library, ‘Security guarantees to Ukraine’, 22 July 2024
• Statement by the secretary of state for foreign, commonwealth and development affairs, David Lammy, on ‘UK-Ukraine 100-year partnership’, HC Hansard, 20 January 2025, cols 733–47

---

Cover image by Number 10 on Flickr.