"NHSBT carries out biannual attitudinal surveys. The fourth wave in 2017, involved 1499 interviews carried out via online self-completion between the 10th and 21st of April 2017. In this wave, 81% of people supported organ donation in principle."
Precisely, this is a bullshit survey with dodgy results. Online self-completion? 1499 participants? If this survey was the basis of this change in law, to be default opt-in, then something very terrible has happened.
https://www.organdonation.nhs.uk/get-involved/news/hundreds-...
But alas, no methodology and questions on that page.