Alex is a white, English, low-paid worker. In fact, not only is he low-paid, but until recently he was being denied even the most basic employment rights, such as paid holiday and a pension. A pushbike courier in the Doctor’s Laboratory’s in-house courier department, Alex works alongside another hundred or so pushbike, motorbike and van couriers. A large proportion of these workers are Brazilians, able to live and work in the UK by virtue of dual citizenship with EU countries.

After various unfruitful attempts at improving his working conditions on his own, he turned to the Independent Workers’ Union of Great Britain (IWGB), a trade union founded by Latin American cleaners. With the Union’s help, Alex and his colleagues went on to unionise the majority of the company’s couriers, and brought a court case that resulted in the company recognising couriers as limb (b) workers and thus entitled to basic workers’ rights; won a collective bargaining deal to negotiate pay, terms and conditions; and are party to a backdated holiday claim worth over £1m. Their fight for better pay continues as part of an ongoing union campaign.

Alex’s story is illustrative of both the root causes of labour exploitation as well the solutions. For imagine a world in which Alex had instead bought into to the xenophobic scapegoating that characterised the leave campaign by blaming his Brazilian colleagues for his plight. Despite the best of intentions, distilling any practical solutions from the hysterical rhetoric of the Brexiteers is almost as hard as negotiating a comprehensive trade deal with the EU in two years. But presumably the Brexiteers’ solution to Alex’s problems would be for Alex to vote leave and then sit back in the hope that eventually fewer Brazilians with EU passports would be working with him, and that that eventually might increase his wages and improve his terms and conditions and treatment at work.

Of course, with the end of free movement, the supply of EU workers to Alex’s workplace does not dry up in isolation. For so too dry up the European patients who send their blood samples to be couriered by Alex and the other EU workers who participate in the economic ecosystem in which Alex’s employer operates. Every worker is also a money-spending consumer; low-paid workers proportionately more so. But fundamentally, it is not Alex’s foreign-born colleagues that have suppressed his wages and deprived him of rights: it is decisions by management.

Further, the Tories – who have an incredible capacity for temporarily mending Brexit fractures for the purpose of uniting behind policies which are bad for workers – have repeatedly erected roadblocks to the actual solutions to Alex’s problem. The passing of the Trade Union Act made union organising and action more difficult. The employment tribunal fees regime, until declared unlawful, rendered the enforcement of individuals’ employment rights impossible for many. The government continues to adamantly refuse to enforce employment law in a serious way, and so gives employers a green light to ignore it. Combined with eight years of austerity, it’s hardly a surprise that economic insecurity is a defining feature of our times. Despite a bit of lip service to exploited workers, the prime minister’s plan of action was confined to the Taylor review of modern working practices, which offers little to the workers in question, and whose recommendations are wholly inadequate to solve Alex’s problems.

The government’s priorities in this regard are reflected in its proposed withdrawal agreement. While, as the prime minister has been keen to remind us ad nauseam, the agreement would end free movement (her “reddest of red lines”), it also paves the way for the watering-down of our employment rights. The government’s approach to immigration – running a strict enforcement regime with real sanctions, keeping the regime under review, and constantly expending political capital on it – is the right solution to the wrong problem. Were they to take the same approach with our employment rights, we might get somewhere.

This country is on the verge of momentous decisions, the ramifications of which will be acutely felt by low-paid workers for a generation or more. What’s on offer is a clampdown on migration, the throwing up of borders, and a validation by government that indeed the cause of British workers’ problems is their foreign-born co-workers. And not much else.

If the question is how to deal with labour exploitation, the answer lies in improved and enforced employment rights, and a unionisation strategy based on uniting workers, vigorous campaigning and effective collective bargaining. If you don’t believe me, just ask Alex.

• Jason Moyer-Lee is the general secretary of the Independent Workers’ Union of Great Britain