My Lords, I can be very brief in supporting this amendment, which has my name on it. Saying that is a very ominous start; it usually means the exact opposite, like the phrase “with the greatest respect”. But I can indeed be very brief because, on 18 April, I proposed and the House approved, by a majority of 123, a very similar amendment on the European Union (Withdrawal) Bill. With the greatest respect, I have to say to the Government that we would not be in the present predicament if they had listened to what the House said on 18 April.
The economic case for a customs union if we leave the European Union is pretty well understood now. Business is explaining ever more volubly how damaging supply chain disruption would be. With the greatest respect for No. 10, I do not believe that the red line against a customs union would have been drawn in the 2016 party conference speech had there been any consultation with business, Parliament or the Cabinet beforehand. The political case for a customs union has become even more familiar as we think about the concept of a customs frontier across the island of Ireland and a backstop with a frontier down the Irish Sea. With great respect, I have to say that it was unfortunate that the 2016 announcement of the red line on a customs union, interpreted in Dublin as a declaration of intent to abrogate the Belfast treaty, was made without any advance consultation with or notification to the other parties to the treaty, and with no consultation with this Parliament or with the Northern Ireland Assembly, which at the time still existed.
Taken together, the economic and political case for a customs union, if we leave the European Union, looks pretty overwhelming—but I see no reason to labour the point now. I recognise that the Minister cannot accept the amendment, and we all know that much may have changed before the House considers this Bill again on Report. I simply urge the Minister, with the greatest respect, to ensure that her colleagues remember how this House voted on 18 April.