https://www.nao.org.uk/wp-content/uploads/2018/10/The-UK-border-preparedness-for-EU-exit.pdf
https://blogs.lse.ac.uk/brexit/2019/10/09/northern-ireland-depends-on-the-eus-fluid-borders-for-survival/
http://news.sky.com/story/theresa-may-theres-no-economic-case-for-breaking-up-the-uk-10787816