https://yougov.co.uk/news/2017/04/26/voting-intention-conservatives-45-labour-29-25-26-/
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/655232/DExEU_ARA_v5.0_amended_version_14.08.17__1_.pdf
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/994125/FINAL_TIGRR_REPORT__1_.pdf