https://publications.parliament.uk/pa/cm201719/cmselect/cmhaff/421/421.pdf
https://www.gov.uk/guidance/status-of-eu-nationals-in-the-uk-what-you-need-to-know
https://blogs.lse.ac.uk/brexit/2019/12/03/a-missed-opportunity-revisiting-the-euro-referendum-that-never-was-from-a-historical-perspective/