Wrong. Quite spectacularly wrong. And worrying that we still haven't learnt much about negotiations. Domestic debate does not actively damage a country's negotiating position. It is normal.

In fact the best negotiators use the different elements of domestic debate to their advantage. Something that almost every trade negotiating expert has pointed out the UK has denied itself by an overwhelming belief in secrecy and not telling Parliament much.

Also a highly political statement for a government advisor to make, that the views of a senior MP are not welcome on a negotiation. Clearly the battle for Brexit ranges just as intensely as it ever did within the Conservative Party.

And though there is some discussion about this I still think at core the ERG does not want an EU trade deal. Because a deal means compromise, and compromise is inconsistent with alternate realities. It all sets a precedent for future deals with the EU.

If the Conservative Party was united about a deal the PM would have done it weeks ago. It isn't, and that is the delay. Technical issues are not sufficiently difficult to prevent a deal and haven't been for many weeks. This remains all about the political decision. Or not.

From my last Brexit article, four weeks ago. Nothing fundamental has changed. Deal or no-deal is still all about the messy internal politics of UK and EU. https://www.prospectmagazine.co.uk/economics-and-finance/the-obstacles-to-a-brexit-deal-are-not-what-you-think