There is a pervasive idea on the internet that the popular vote is the "real" vote, compared to constituency-based voting. I don't find that to be a helpful attitude, especially when applied selectively. We live in a representative democracy, not a direct democracy. The House of Commons is a constituent assembly, which is a valid and reasonable form of democratic representation. The election system could be changed to better reflect the popular vote, but the popular vote is not automatically more valid than the constituency-based system. There are pros and cons to both, with constiuency-based voting typically giving somewhat more weight to under-populated areas.

The fact is that the UK voted for Brexit, directly and indirectly, multiple times and in multiple ways using its long-established voting system. There is no way to escape responsibility. Indeed, being a democracy, the citizens of the UK are ALSO responsible for their own voting system.