https://www.instituteforgovernment.org.uk/sites/default/files/publications/voting-on-brexit-report-final.pdf
https://conservativehome.com/2022/05/11/the-northern-ireland-protocol-the-options-boil-down-to-hoping-the-eu-backs-down-or-offering-it-a-new-deal/
https://www.nao.org.uk/wp-content/uploads/2017/07/The-Customs-Declaration-Service.pdf