When UK Brexit negotiators rejected proposals for a Northern Ireland-only customs arrangement backstop in favour of a deal that would involve continued all-UK membership of a customs union they tacitly accepted that the UK's long term future would be in a customs union.
This is the case whether or not they acknowledged it publicly, and whether or not it meant crossing one of their own red lines.
That temporary all-UK customs arrangement is now a central element in the draft withdrawal agreement that is being pored over in London and across Europe.
The move, the UK argued, was necessary to prevent the emergence of a border in the Irish Sea, in effect to minimise the economic and customs barriers that would be necessary between Northern Ireland and the UK to safeguard the integrity of EU’s single market and the frictionless Border in Ireland. But that decision came at a price.
In the Commission’s original plans, the backstop mechanism would kick in after transition “unless and until” a “future relationship” deal provided better protection for the frictionless border. If that deal was not agreed or took years to agree the North was to have remained in its own customs union with the EU, while the rest of the UK forged its own way on the world stage.
But now, during that interim period, the UK as a whole will remain in a customs union, perhaps indefinitely. And there will be special regulatory alignment measures for the North to tighten protection of the EU single market.
British prime minister Theresa May has also reportedly agreed to “level playing field” measures tying Britain to EU rules in areas such as state aid and environmental and workers’ rights protections during the backstop. What has become clear is that UK negotiators accept the logic that any future relationship deal will also have to be based on a customs union agreement, supplemented by many of the regulatory requirements of the single market.
Briefing EU ambassadors on the proposed deal on Monday, EU deputy chief negotiator Sabine Weyand is reported to have admitted as much.
“We should be in the best negotiation position for the future relationship. This requires the customs union as the basis of the future relationship,” Ms Weyand is reported to have said according to a leaked diplomatic note of the meeting.
The implication is the backstop is permanent and the UK will stay in the customs union forever. How that reality is to be reconciled with the UK’s determination to strike its own trade deals internationally is not clear – what it means, at the least, is that its ability to do so will be constrained for some years.