The Tory Brexit shambles appears to know no end. The grandstanding over the divorce bill, including Boris Johnson’s “go whistle” moment, has all been a waste of time as David Davis might finally have conceded that we will pay the EU the legitimate cost of breaking our contract with it – a sum of between £50bn and 60bn.

But the Tory posturing has cost us more than just money. By poisoning the diplomatic well they have left us with next to no friends among our EU partners and leave our international standing even further on the slide.

We represent workers from across these islands, and all are united in their condemnation of any return to a hard border in Ireland

In Tory hands, the UK’s future relationship with the EU is guided by what plays well with the party, not the national interest. Frankly, irrespective of which way you voted in the EU referendum, we all deserve better from our government. We are still a long way from agreeing an EU exit package that puts our rights, our jobs and our livelihoods first.

The thorniest of all our problems is the position into which the Tories have thrown the Irish peace process. This is very close to the hearts of our members’ union, as we represent workers from across these islands, and all are united in their condemnation of any return to a hard border in Ireland.

This week I addressed Labour MEPs and urged them to work with their socialist colleagues in the European parliament to block any deal that fails to guarantee a soft border. The truth is that some form of EU customs union will have to be in place for Ireland to maintain its current cross-border freedoms: there is no other way around it. The Tories and their media cheerleaders must stop pretending otherwise and engage with reality. They must end the disgraceful English nationalist, jingoistic and xenophobic statements about our Irish partners.

It is also a priority that we resolve the question over the rights of EU nationals within our borders. These citizens are still being used by the Tories as bargaining chips when they need certainty and security. It is both logical and reasonable to grant the European court of justice (ECJ) continued jurisdiction over them to ensure their protection. Rather than string out another pointless, uncivilised row, the Tories should ditch their unhelpful rhetoric and accept the European court’s jurisdiction over its citizens in our nation post-Brexit.

Even if all of the above is settled, we will still be a long way away from defining our future trading relationship with the EU, and the trickiest part of the negotiations is yet to come. Take our car industry, for instance. Its just-in-time production model means that the components needed to build saloons or hatchbacks in Sunderland or Derby or Ellesmere Port are sourced throughout the EU and transported across multiple borders with minimal delay. But as Honda recently pointed out, there are no frictionless borders outside a customs union. This may mean just-in-time production methods are no longer viable in a post-Brexit Britain.

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Warnings of car plants possibly relocating out of the UK are already a reality. There is also the prospect that cars made here will face tariffs when exported to the EU, making the future of the car industry here yet bleaker. The same dismal outlook now applies to anything else exported from Britain to Europe.

Labour’s front bench is right to say it is leaving all options on the table, including remaining within the customs union. This is a pragmatic way of both protecting our jobs and ensuring there is no hard border in Ireland. It would also enable the EU to agree trade deals on our behalf – although the question remains as to why we would go from rule makers to rule takers, as Brexit implies.

If, in order to protect our livelihoods and our peace processes we need to stay in the customs union, let’s go the whole hog – let’s stay put in the EU to retain our seat at the top table. Let’s continue shaping our future, rather than letting others do it for us. And let’s keep Ireland without hard borders.

• Manuel Cortes is general secretary of the Transport Salaried Staffs’ Association