https://www.gov.uk/government/news/david-davis-speech-to-the-suddeutsche-zeitung-economic-summit
https://centreonconstitutionalchange.ac.uk/sites/default/files/2021-04/Union%20at%20the%20Crossroads.pdf
https://www.politico.eu/article/9-slippery-brexit-pledges/?utm_source=POLITICO.EU&utm_campaign=39a5c3d811-EMAIL_CAMPAIGN_2019_11_01_05_51&utm_medium=email&utm_term=0_10959edeb5-39a5c3d811-190380769
http://cdn.budgetresponsibility.org.uk/July_2017_Fiscal_risks.pdf