
https://www.instituteforgovernment.org.uk/sites/default/files/publications/IfG_Brexit_customs_WEB.pdf

https://blogs.lse.ac.uk/brexit/2019/08/12/boris-johnsons-real-agenda-the-singapore-scenario/

https://www.cips.org/en/news/news/businesses-preparing-to-sever-supply-chain-ties-between-the-uk-and-the-eu-to-avoid-brexit-tariffs/