Uncertainty over Britain’s defence spending plans is raising questions over how the UK will fund commitments made under its new defence and security treaty with Poland, a House of Lords committee has warned.
The International Agreements Committee said the UK-Poland Defence and Security Partnership represented an important strengthening of relations with a major NATO ally, but warned that a lack of clarity over future defence funding could undermine implementation of some of its commitments.
The treaty was signed by former Prime Minister Sir Keir Starmer in May 2026 and was described at the time as “the biggest step forward in our defence and security relationship with Poland in a generation”.
It commits Britain and Poland to closer cooperation across defence and security, including ambitions to become joint European leaders in the development and manufacture of the next generation of missiles.
In its report published on Wednesday, the committee said it was “concerned about how the Treaty’s commitments on security and defence will be funded in light of the UK’s defence spending plans”.
It warned that uncertainty over funding may “not only undermine the UK’s reputation as a key partner in security and defence at a time of geopolitical uncertainty, but also limit the UK’s ability to respond to increasing challenges from hybrid threats”.
The committee nevertheless welcomed the treaty as an important step in strengthening bilateral relations with Poland, particularly against the background of Russia’s war against Ukraine and the wider deterioration in European security.
It also welcomed recognition of Poland’s “crucial” role in the Euro-Atlantic security architecture and backed measures to deepen cooperation on hybrid threats and defence industry activity.
The agreement extends beyond traditional military cooperation into areas including national security, economic resilience, energy and climate security.
Questions over detail and mutual defence
Despite supporting the overall direction of the treaty, the committee concluded that many of its provisions were expressed in high-level terms and lacked sufficient detail on how they would be delivered.
It also questioned whether the treaty’s mutual defence provisions created substantial new commitments beyond the obligations Britain and Poland already have to one another as members of NATO.
Lord Johnson, Chair of the International Agreements Committee, said: “As this Treaty recognises, Poland is a crucial ally for the UK and plays a vital role within the NATO alliance. We welcome the strengthening of UK-Poland cooperation under this Treaty, particularly in tackling hybrid threats and strengthening defence industry cooperation, though we also found that much of the Treaty is rather general in nature and lacking in substance.”
He added: “We are concerned, however, about how this Treaty’s commitments on security and defence will be funded in light of the UK’s defence spending plans. Many of the Treaty’s commitments are laudable, but without adequate funding it is unclear how they will be implemented. We would welcome further clarity on this from the Government.”
The committee has also asked ministers to clarify the practical significance of the treaty’s mutual defence provisions.
Lord Johnson said: “We have also asked the Government to clarify whether the Treaty’s mutual defence provisions are meaningful, given that the UK and Poland are already committed to defend each other under NATO.”
