Populist claims that migrants heap pressure on the NHS and swamp schools by having more children have been debunked in a major international review which finds they are actually healthier and reproduce less than non-migrants.

Stricter anti-immigrant policies, like the UK’s “hostile environment”, actually increase the risks and costs for health systems and reduce GDP, the Commission on Migration and Health claimed.

This was particularly true for the UK, where 37 per cent of NHS doctors qualified overseas and migrants accounted for a disproportionate amount of the care workforce - which is currently in the middle of a major staffing crisis.

“Migrants are healthier and contribute to our economy and the NHS,” said Professor Ibrahim Abubakar, the commission’s chair from University College London (UCL).

“There is no evidence that migrants are a drain on the NHS or that they spread infectious disease.

“Exclusion of migrants in health systems and the increasing negative rhetoric is political and not evidence based.”

The commission’s report includes new research showing the migrant population globally is less likely than the native population to die of heart disease, cancers or injuries.

Only deaths from assaults and infectious diseases like pneumonia and HIV were higher in migrants, but there was little evidence of this posing a health risk outside migrant communities.

The new report comes after Italian officials used spurious health fears about HIV being transmitted on refugees’ clothes to seize a rescue ship.

The commission also reviewed existing evidence to identify whether there was any grounds to the idea that high birth rates add to pressures on services.

In a review of six European countries, including the UK, it found virtually all groups – except Turkish migrant women – had fewer children than the native population.

Professor Abubakar added that the “hostile environment” introduced under Theresa May’s tenure as home secretary has had “direct severe public health and health economic consequences”.

The measures led to Windrush generation British citizens being denied treatment, or deported midway through being treated, and introduced upfront charges for visitors requiring hospitalisation that has caused some patients to delay cancer treatment.

The hostile environment also led to the NHS agreeing to hand over patient information to immigration enforcement officials, a measure which made patients less likely to seek support and may have led to deaths and infections.

The commission, led by UCL and the Lancet medical journal, is calling for governments to remove barriers for migrants accessing treatment and help tackle ill health and discrimination.

The report involved experts from 13 countries, working over two years, and is published in The Lancet before presenting its recommendations for improving migrant health at a UN meeting on Saturday.

Professor Terry McGovern, another of the report’s authors from Columbia University, said similar anti-immigrant myths were driving harmful policies in America.

“Contrary to the current political narrative portraying migrants as disease carriers who are a blight on society, migrants are an essential part of economic stability in the US,” said Mr McGovern.

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“The separation of migrant children from their parents creates long-term psychological damage – and is a cruel and unnecessary aspect of US policy.

“The criminalisation and detention of migrants seeking internationally protected refugee status violates international law, and puts them at greater risk of ill health.