Uniform Title Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland Regarding Mutual Assistance in Customs Matters between Their Customs Administrations (2020 December 16) Title Law enforcement : customs administrations : agreement between the United States of America and the United Kingdom of Great Britain and Northern Ireland, signed at London, December 16, 2020; entered into force January 1, 2021.