European Union (Withdrawal) Bill

Is there not a deep misunderstanding among those who say they want free trade agreements but to be outside the customs union? Creating a customs border is independent of how much we actually raise tariffs, because there will still be a border and there will still be checks. However freely or not freely we trade, creating a customs border will lead to delays, checks, regulations and so on and so forth. People say that we will have a great free trade deal, but we will still have a border, and that is what will be damaging.