MPs who vote for a customs union tonight are wasting their time – the EU has already got everything it wants

Brexit has become a bundle of complexity. Even now, few people have read the 585-page withdrawal agreement and even fewer understand what it says. As the indicative votes process takes place today, parliament looks set to support adding a permanent customs union to the political declaration – the statement of intent agreed between the UK and the EU on their post-Brexit partnership – while leaving the legally-binding withdrawal agreement unchanged. Here’s why that’s pointless.

The withdrawal agreement allows for a transition period to the end of 2020 where the UK will remain inside all the main EU structures, but outside the political decision-making. During this period, the UK and EU are supposed to negotiate a new agreement – one that covers nearly half our international trade. The agreement allows for the transition to be extended just once, and at the cost of around £1bn per month. If the Conservative government survives, expect it to extend the transition to just before the scheduled 2022 general election.

At that point, either the UK and the EU have concluded a new agreement that solves the Irish border issue, or the UK enters the “backstop”. But in the absence of any known solutions to the Irish border problem, the backstop isn’t a fall-back but rather the default. The agreement might as well require the UK government to present the European Commission with a jar of magic beans or arrive at the next summit on a flying carpet. So the backstop must be assessed as the destination, not as an insurance policy. And at the heart of the backstop is a UK-wide customs union with the EU.

For the EU, the Irish border was the most significant political negotiating objective, securing the peace and demonstrating how membership amplifies the power of individual nation states. But after defending the integrity of the single market, the most important economic objective was a customs union that would enable free trade in goods. That’s because the EU sells £95bn more in goods to us than we sell to them.

It was always said that the EU was skilled at negotiation, but this is on another level. It is a case study in negotiating genius. The EU said that Article 50 meant that the divorce deal would have to be agreed first, and only after the UK had left the EU could the future partnership be discussed. Yet through the device of the backstop, they have already secured their most important negotiating objective for that future partnership. A customs union by stealth should be opposed by Leavers and Remainers alike, albeit for different reasons.

Brexiters oppose membership of a customs union because they fantasise about the possibilities of an independent trade policy. This is delusional: first, there is no evidence that agility trumps scale in trade negotiations – in fact, bigger economies get better deals. Second, the UK is advantaged in the exports of services, which are delivered by people and are much more affected by non-tariff barriers, meaning that immigration rules and regulatory alignment are what matters – a customs union addresses neither. Third, the demise of the UK’s manufacturing industry means that the problem is not the quality of trade deals but rather not having enough to sell to the world.

But for advocates of a soft Brexit – including the Labour Party – why should the backstop even matter? They want a customs union anyway, so what’s the difference? The problem is the lack of control. Too little attention has been paid to the risks of being within a customs union without a say. Through the backstop, the withdrawal agreement emasculates the UK in international trade: it stealthily puts us into a customs union without a say and with no safeguards in place.

“If you are not at the table, you’re on the menu”: with no say for the UK, in all future trade negotiations, EU negotiators will be able to put the British economy on the table – without us being in the room or able to refuse. Contrary to the free trade ideologues, all the evidence suggests that while in the aggregate trade liberalisation is good, it creates winners and losers. Why wouldn’t the EU concentrate the gains in the EU27 and the losses in the UK? Put crudely, imagine the UK being subject to aspects of a Trump-EU trade deal that it had no say in and could not refuse.

As Olly Robbins said, the future partnership is supposed to be built on the withdrawal agreement. With the UK having already conceded a no-say customs union through the withdrawal agreement, there is no conceivable reason why the EU would agree to a negotiated customs union with the necessary safeguards, even if it were to be included in the political declaration. So parliamentary support for a customs union is completely pointless.

This is not normal. Approximately 100 countries are in one of around a dozen customs unions around the world and they all have complex decision-making structures and processes to make sure they are fair. But more than that, a customs union by itself is insufficient to achieve frictionless trade, which requires aligned regulations, and does nothing for services exports, where the UK currently sells £28bn more a year to the EU than it sells to us. So a customs union should not be mistaken for a soft Brexit.

As voting takes place again this week, MPs need to avoid being distracted by confused arguments. The withdrawal agreement is a bad deal for the UK, failing to secure our national interests or to satisfy either Leavers or Remainers, and adding a customs union to the political declaration makes no material difference. And that’s why we should expect that MPs will continue to vote it down.

Tom Kibasi is director of the Institute for Public Policy Research, a progressive policy think tank