
https://blogs.lse.ac.uk/brexit/2021/02/04/indyref2-scottish-independence-would-be-2-3-times-more-costly-than-that-of-brexit-and-rejoining-the-eu-wouldnt-make-up-the-difference/

https://www.gov.uk/government/news/david-davis-teesport-speech-implementation-period-a-bridge-to-the-future-partnership-between-the-uk-eu

https://ec.europa.eu/commission/sites/beta-political/files/customs_controls_0.pdf