https://publications.parliament.uk/pa/ld201719/ldselect/ldeucom/63/63.pdf
https://www.gov.uk/government/speeches/eu-speech-at-bloomberg
http://www.guengl.eu/uploads/news-documents/Working_paper_Border_controls_on_cross_border_trade_in_goods.pdf
https://committees.parliament.uk/publications/30492/documents/175947/default/