Brexit and the economy

Axios notes:

An analysis from the U.K. government anticipates entirely negative economic impacts from Brexit regardless of the terms of the exit deal, Buzzfeed News, which got its hands on the analysis, reports.

• Top-line figures: Growth would fall by 8% over 15 years under a "no-deal Brexit," 2% under a "soft Brexit" and 5% under a middle course. Nearly every economic sector would be hurt, with the exception of agriculture, along with every geographic region.

The bottom line: The British government is going to spend the next year or so in intense negotiations over a process its own analysis suggests will bring entirely negative economic consequences.

Seriously, why would a sensible government continue down that path when it believes those are the consequences?   

Update:  Simon Wren-Lewis writes about Brexit and the Conservatives:

This Brexit syndrome, which infects nearly half the Conservative party MPs and most of its membership, is a visceral dislike of the EU in all its manifestations. I am not talking about why most voters chose to leave, which was an unfortunately all too familiar reaction to a public campaign that has blamed immigrants for every grievance and fear they have. Brexit syndrome is instead manifested in a belief that you must leave a customs union with your overwhelmingly biggest trading partner so you can seek inferior trade agreements with other more distant countries. The only explanation for that belief is a deep irrational dislike of all things EU.

For those Conservative MPs not subject to Brexit syndrome I have bad news. Leaving the EU as planned is not a cure. The nightmare of Brexit will not pass. Whatever deal the UK eventually concludes with the EU, it will be unacceptable to the Brexiters. Only a clean break with all things EU will satisfy them.