Some time ago Shanker Singham, from the IEA had an article in CapX trying to play down the Irsh border problem and offering what he claimed were solutions (HERE). Now an academic, Katy Hayward at UK in a Changing Europe, has written a response to his piece (HERE) carefully explaining why his "solutions" won't work.
She quotes him from his original article:
For there to be no change at all at the Irish border would require the entire UK to be in the Customs Union and Single Market, which would eliminate any possibility of an independent trade policy.
This is the problem he is trying to avoid. But Johnson has already said there won't be any change (because Johnson, although not an idealogue, believes those who are) to the border in Ireland but Singham now admits there will have to be changes - otherwise we will have to stay in the EU.
They are trying to square a circle that cannot be squared.