An official at the UK's top financial watchdog has admitted that immigration is putting public services under intense pressure.
David Miles, an economist at the Office for Budget Responsibility (OBR), said the UK's dependency on foreign workers "could not be sustained".
The OBR also conceded that low-paid migrants are a net drain, costing UK taxpayers £150,000 per person by the time they reach the state pension age.
Miles urged the Labour government to focus on the UK's domestic worklessness problem rather than rely on high levels of immigration.
In an essay published by the Common Good Foundation, Miles wrote: “Immigration which primarily involves those of working age, delays the impact of the ageing of the population and is the driver of population growth.
“Some conclude a faster rise in the population will be beneficial in alleviating acute underlying fiscal pressures.
“But there are serious problems with that idea.”
He added that migrants still use public services, such as schools and hospitals, and eventually become eligible to claim benefits.
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|Miles urged the Labour government to focus on the UK's domestic worklessness problem rather than rely on high levels of immigration
The economist said that he believed that the government must get to grips with the surge in economic inactivity that has sharply risen in the aftermath of the pandemic.
He said: "The fiscal benefits of helping people, especially young people, back into employment are substantial.”
According to data released in May, 923,000 young people aged 16-24 are currently not in education, employment or training.
A spokesman for the Treasury said: "Under the last government, Britain’s economy became addicted to cheap overseas labour and relaxed visa controls that saw net migration explode to nearly one million.
"Businesses were encouraged to bring in low paid workers rather than train our young people."
According to the Office for National Statistics (ONS), the population of England and Wales increased by over 700,000 in the year to June 2024.
This population rise was the second-largest since records began, only topped by the rise of 800,000 recorded in the previous year.
This boom was attributed to a record rise in net migration.
Miles said that carrying on these trends would be "unsustainable" as it would add a "substantial" burden to the country's public finances.
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|According to the Office for National Statistics (ONS), the population of England and Wales increased by over 700,000 in the year to June 2024
He noted: “Twenty million extra young people would need to arrive in the UK over the next 40 years to stabilise the dependency ratio at its current level.
"That would imply a UK population of around 100 million by 2064.”
The economist's comments come after growing scrutiny for the UK's benefits bill after a backbench rebellion forced the Labour government to water down their proposed welfare reforms.
The cost for people on disability or sickness benefits is set to reach £100billion by 2030.