The core claim is accurate. The UK Government has the power to make treaties under its prerogative powers, and treaty-making remains the exclusive responsibility of the UK Government; the FCDO also says the Secretary of State is responsible for concluding treaties involving the UK. Official Home Office material lists bilateral UK extradition agreements, showing that extradition treaties are part of the UK’s treaty-making practice. So the UK can choose whether to enter into an extradition treaty, although it still needs the other state’s agreement and, once signed, is constrained by the treaty process. (commonslibrary.parliament.uk) Sources: House of Commons Library, “Parliament’s role in ratifying treaties” (commonslibrary.parliament.uk); GOV.UK, “UK Treaties” (gov.uk/guidance/uk-treaties); GOV.UK/Home Office, “Mutual legal assistance and extradition: treaty list (accessible version)” (gov.uk/government/publications/international-mutual-legal-assistance-agreements/mutual-legal-assistance-and-extradition-treaty-list-accessible-version); House of Commons Library, “Treaty-making and parliamentary scrutiny: recent developments” (researchbriefings.files.parliament.uk/document/CBP-10116/CBP-10116.pdf).