We shall come to the politics of Labour’s latest Brexit policy in a moment. Meanwhile, let us consider the substance.

Labour has tabled the following amendment to the EU Withdrawal Bill:

“It shall be a negotiating objective of Her Majesty’s Government to ensure the United Kingdom has full access to the internal market of the European Union, underpinned by shared institutions and regulations, with no new impediments to trade and common rights, standards and protections as a minimum.”

The amendment is new, but the underlying policy is not. In last year’s election manifesto, the party promised

“a strong emphasis on retaining the benefits of the Single Market and the Customs Union—which are essential for maintaining industries, jobs and businesses in Britain. Labour will always put jobs and the economy first.”

The new amendment uses different words but sets out much the same objective. British industry would obey the same rules as the 27 countries remaining in the EU. As a result it would enjoy frictionless trade. The Irish border would remain open; lorries would not be delayed at Dover.

One of the objections to this is that the UK would become a rule-taker, not a rule-maker: we would have to apply whatever regulations agreed by the EU. Far from “taking back control,” the UK would have less say in what happens at home than it does now. In Jacob Rees Mogg’s vivid language, the UK would become a “vassal state.”

Labour responds in its new amendment by proposing “shared institutions and regulations.” These would give us a seat at the rule-making table. It is an alternative to an amendment passed by the House of Lords, on which Labour is asking its MPs to abstain. This proposes that the UK should remain a member of the European Economic Area, alongside Norway. We would then be subject to what Norwegians describe as “fax democracy”—simply being told what to do by Brussels whenever it wishes to implement a new directive. Labour’s amendment is design to avoid that trap.

Here’s the problem. There is one, and only one, way of continuing to have a say in Customs Union and Single Market rules. That is to remain a member of the EU. If we leave the EU, we shall lose our seat at the table. The notion that the EU would create “shared institutions” to give the UK a meaningful say post-Brexit is—how shall we put this?—fanciful. It would be like a golfer resigning from her club, but still wanting to play on the course, buy drinks at the bar, and have a veto on the decisions of the club’s management committee.

The central question remains for Labour, as it does for the government: what matters more, prosperity and living standards, or the repatriation of laws, rules and regulations from Brussels?

This brings us to the politics of Labour’s continuing dilemma. The party’s leadership is fearful of Labour supporters in Leave-voting constituencies deserting the party if it fails to enhance UK sovereignty after Brexit. This fear, however, may be misplaced. A recent Deltapoll survey for the Financial Timesfound that, by a 62-29 per cent margin, Labour supporters think

“It’s vital for jobs, investment and living standards here in the UK for us to continue to trade as freely with the EU as we do today, even if this limits our freedom to decide our own business and trading rules,”

rather than

“It’s vital that Britain regains the right to decide its own business and trading rules, even if this reduces our ability to trade freely with the EU and risks being bad for jobs, investment and living standards”

That is not all. This week, Michael Thrasher, election number-cruncher par excellence, made a presentation in Westminster to the new All Party Parliamentary Group on Psephology. He analysed last month’s local elections, in which Ukip’s support collapsed, and concluded that voters’ views on Brexit were a symptom, rather than a cause, of shifting Labour and Conservative fortunes. That is, traditional party loyalties have been changing in recent years not because of Brexit per se, but because of underlying social and economic factors to do with technology, jobs, housing, stalled living standards and growing pessimism in parts of Britain about the future.

The lesson is clear. The party that will triumph in the coming years is not one that sticks dogmatically to any particular stance on the EU. It will be the one that is best able to persuade voters that it can chart a path towards a more prosperous economy, a stronger society, a revived NHS and access to better jobs and homes for younger people.

So, when Labour finally has to climb down from the fence and choose between the economy and sovereignty, base electoral calculation should lead it to the same conclusion as long-standing pro-European principle. Better to drop the insistence on “shared institutions and regulations” than dilute its insistence on “full access to the internal market of the European Union.”