Lawrence Tilney dates the death of British democracy to March 29, 2019 because the UK did not slavishly follow a narrow referendum result.
Of course, referendums are always sacrosanct if they happen to coincide with your own opinions. Whether many of the Brexit voters were really voting for a reduction in their standard of living and the wasting of billions of pounds on exit preparations is a moot point at best.
Recently, in Switzerland, the Supreme Court declared a referendum result void because the voters had been given so much erroneous information. In Britain, Brexit politicians told the public they could have their cake and eat it, able to spend mega-cash on the national health service rather than on Brussels bureaucracy.
Personally I think democracy died when Guy Fawkes got caught with the gunpowder.