The relationship between Migration Watch and the press is basically that of a conveyer belt. They release an alarming report about how many migrants are coming to the UK, or how much they cost UK taxpayers, and the press treats it like some respectable piece of academic research.

But Migration Watch doesn't produce academic research. It produces whatever logical contortion is required to turn facts about immigrants into a weapon to beat them with. They'll say anything, or ignore anything, in order to turn the UK's political debate against migrants.

Their report today forecasts - you guessed it - huge future waves of migrants coming to the UK if we leave the EU. Under a 'low migration' scenario, we'd have another 3.4 million EU migrants here by 2035. Under a 'high migration' scenario, we'd have 4.3 million. It's weaponised for tabloid coverage.

How is Migration Watch working out these figures? Well, they argue that "immigration is mainly driven by differences in wealth and opportunities between countries".

How come anyone leaving to the left is called 'left wing' but Migration Watch quoted as tho not a right wing vested anti EU interest? — Alastair Campbell (@campbellclaret) 13 June 2016

In reality, Migration Watch's report doesn't show that "differences in wealth" trigger migration. It shows that job availability triggers migration. Where there is work, people come. Where there isn't, they don't. Immigration is a product of economic progress. But we can't admit this, because it would prevent the anti-immigration lobby from blaming immigration for everything. And it would disprove the central idea behind the Migration Watch report, which is that the structure of the single market will always lead to massive inflows of migration to Britain, regardless of economic circumstance, because of the relative poverty of eastern European countries compared to the UK.

"The minimum wage in the UK, between 2010 and 2015, was over three times higher than in Poland," the report says. "The economies of eastern Europe are forecast to grow over the next couple of years and both Romania and Poland have raised their minimum wage in 2016. Yet the economic incentives to move to the UK will remain strong as incomes will still remain substantially lower than in the UK."

The usual anti-immigration argument that low skilled eastern European labour is driving down wages is suddenly reversed. For Migration Watch, it's now specifically high wages which bring people over. "The UK national minimum wage, now set on an upward course, will add significantly to the pull factor and ensure that a substantial difference remains between basic wage levels in the UK and those in central and eastern Europe - the main driving force for migration," they say.

All of which raises a pertinent question. Why has migration picked up since 2010? After all, wages were higher throughout, so if that's the main driving force, you'd have expected migration levels to stay level. Migration Watch's answer is that "the UK returned to economic growth in 2010". So suddenly differences in wages aren't "the main driving force" anymore.

The usual guff we hear about migrants claiming benefits has also been repackaged. Supporters of immigrants have argued for years that they do not come to the UK to claim benefits. Migration Watch now admit this - but only because it allows them to claim more migrants will come anyway. "As most EU migrants arriving in the UK are single or childless couples, they are eligible for only small amounts of benefits even if working at the minimum wage," the report says. "The delay negotiated by the government in this eligibility for in-work benefits will therefore deter few people from migrating to the UK."

How odd. After all, Migration Watch’s briefing paper on benefits says: “In-work benefits for the low paid are generous in the UK compared to other countries in the EU15 and may act as a much stronger pull factor towards Britain than to other member states.” Now suddenly anti-immigration groups are admitting migrants don’t come to claim benefits, but only because it is politically expedient to them to do so.

There's even a section in which Migration Watch admits that immigrants stimulate demand. But again this must be reformulated in the most bizarrely negative way. "Demand for immigration by employers feeds on itself as the population growth from migration continually increases demand for goods and services, requiring more immigration for its satisfaction", the report says. Even where they admit that immigration is increasing demand and therefore has a role boosting the economy, it is sold in these parasitical terms.

No matter how they try to dress it up, Migration Watch can't deny the economic reality of what they are discussing. At one point they acknowledge that the one thing which would be most likely to reduce immigration would be "a serious downturn in the UK economy". In other words: migration is a consequence of economic good fortune.

These are the intellectual contortions opponents of immigration have to go through in order to make their case. The overwhelming body of evidence showing it is economically advantageous must be ignored. Migrants must be shown to be work-shy benefit-grabbers, or if they can't be, then shown to be so sometime in the future. In summary: they don’t claim benefits now, because that suggests David Cameron’s renegotiation might have an effect. But they will in the future, because then we’ll be back to blaming them for everything.

They must be shown to hammer down wages. Unless there is a minimum wage, n which case we must show that they come for the wages. They are economically parasitical. Unless they are shown to increase demand, in which case they start a cycle of economic bloating.

Whatever they do, however they act, they can't win.

Ian Dunt is the editor of Politics.co.uk

The opinions in politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners