While there are many uncertainties about what Brexit might look like, there is no question that the Tories want to use it to launch a points-based immigration system.

First developed in Australia, this system awards points typically for qualifications, salary, skills and language proficiency. Those with higher salaries, more advanced qualifications or much-needed skills gain extra points in these areas. An applicant needs to earn enough points above a set target in order to immigrate. The system is designed to encourage immigration from highly-skilled and professional workers.

Priti Patel, the home secretary, told the Conservative Party’s annual conference in Manchester that she’d “introduce an Australian style points-based immigration system” into the UK. This will be “under the control of the British Government” and “end the free movement of people once and for all” linking this system with leaving the EU. This is despite the UK having an opt-out on immigration policies anyway.

Patel’s views echo those of most Brexiteers: the UK should end free movement and create a points-based system instead to help “take back control”. In 2015, Nigel Farage and Ukip were calling for starting a points-based system. A year later, Boris Johnson and Michael Gove claimed introducing this system would help toughen immigration controls.

But despite the referendum’s support for Leave, then prime minister Theresa May rejected the idea of having a points-based system immediately. This was partly because she was concerned about abuses of the system that, in her eyes, could let recent graduates qualify despite lacking sufficient English skills. But it was also because the system – as conceived in Australia – was designed to increase immigration while her government actively tried to cut it.

Perhaps unsurprisingly, Johnson hasn’t only done a U-turn, but a full loop. First proposing it during the referendum, then saying he dropped it only to now lead a government in favour of introducing one. Then again, Johnson’s tendency to switch sides and back again isn’t a unique position for him on immigration, or Europe more generally.

From Johnson and Patel to Gove and Farage, the view of Brexiteers is clear: the UK should launch a points-based immigration system and this is what is needed post-Brexit. A big flaw in this argument exposing how little they seem to know about immigration is, well, the points-based system they want so badly is already in place. And thanks to Labour.

In 2008, Gordon Brown started a points-based system. It applied to non-EU nationals only and continues today. I should know – I was admitted through it.

While the official Gov.uk website carries information about the system and how to qualify, it’s mostly something that only immigrants like me that have been through the system would know. The Home Office used to have an online points calculator. This would allow anyone to check and see if they qualified for a visa. I regularly forwarded the link to anyone interested in how a points-based system worked, especially to journalists in order to expose that it already existed.

However, the calculator has been taken offline since the EU referendum was held – perhaps in an effort to hide from the public that the system promised to them by Johnson and Patel is actually already in place.

The good news for the prime minister, home secretary and Nigel Farage is that the immigration system they want is already in place. It’s time they stopped calling for its creation before more people realise their error.

The bad news for them is they should thank Gordon Brown for introducing it. If a points-based system is the future, they owe it to New Labour.

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And the really bad news is that points-based systems increase immigration, create unnecessary complexity and can be difficult to manage.

This is a problem for anyone wanting a fairer, more transparent and accountable system. So the real issue isn’t whether we should launch a system like this, but how we might scrap the one we’ve got. Yet this would require a home secretary who knew how the immigration system she wants to reform actually works.

And as someone who didn’t migrate and has seemingly little understanding of the experiences of migrants like me who have, this gap between her promises and the reality will only grow larger. Maybe Patel won’t take lectures from North London MPs, but perhaps she should sit in a class with a professor with expertise in immigration law.