I have yet to finish reading but this is an excellent breakdown and upholding of Britain’s constitution.
If any blame is to be assigned, it should be to a government (under David Cameron) that held a referendum which was not itself a part of an Act of Parliament to exit the EU based on the results of that referendum.
I find it hard to believe that Cameron was unaware of the need for an Act of Parliament. Although one of the few PMs who was not a lawyer, he was surrounded by them and surely knew enough of constitutional law to have known what he was doing. But then, he never did want Brexit, never even thought it was going to happen and pulled all kinds of tricks to make sure it would not.
That criticism made, I am unsure if other recent referenda were held in the same, informal, manner.