The UK’s general law principle of non-cooperation with foreign jurisdictions in the collection of taxes has been significantly eroded with the introduction of EU Directive 2010/24/EU, which imposes an obligation on the UK to assist any Member State of the EU in the recovery of tax debts, together with the joint Council of Europe/Organisation for Economic Co-operation and Development Convention on Mutual Administrative Assistance in Tax Matters and the UK’s adoption of Article 27 of the OECD Model Tax Convention or similar debt recovery provisions in its double tax agreements. Practical issues for advisers concern the very few limitations on the UK’s obligations to assist in enforcement, the retrospective/retroactive nature of the arrangements and the inability to contesta foreign tax claim in the UK.