In my humble opinion this is one of the best articles on Brexit I have read in years.

I have had no end of discussions where people flip back and forth between Brexit as an event in Jan 21 and an ongoing process. Where purity is more important than reality.

The only thing I disagree with is a bit tongue in cheek. When he says "It is impossible to sit in the Treasury without coming to a rational understanding that the national interest demands harmonious relations with Brussels" we can all think of a chancellor who didn't manage that.