Social care faces a recruitment black hole with potentially hundreds of thousands of positions in the sector remaining unfilled because of the government’s new immigration policy, the union representing care workers is warning.

The GMB estimates the policy will have an impact on up to half a million jobs in the UK. Its analysis of official figures reveals that more than 350,000 adult care workers were born outside the UK in the year to September 2019 – a figure that has risen by 43% in the past decade.

About 115,000 care workers are originally from an EU country and 237,000 workers were born outside the EU. Overall, almost a fifth of the care sector’s workforce was born outside the UK. According to the Office for National Statistics, there are an estimated 110,000 vacancies in adult social care. The sector has a vacancy rate of 8%, compared with an average of 2.8% across all sectors.

For the home secretary to brand the care workers our whole society relies on as ‘low-skilled’ is a bit rich Rachel Harrison, GMB

Under immigration rules, due to come into force on 1 January 2021, most businesses will be barred from recruiting overseas workers for jobs that pay less than £25,600 a year. The average salary for care workers employed by private providers was £16,200 last year, according to Skills for Care, which collects data on behalf of local authorities and the government.

But care workers will not receive special visa dispensation, unlike graduates, scientists, NHS staff and agricultural workers. Priti Patel, the home secretary, dismissed concerns over the immigration reforms and insisted that any labour shortages could be filled by recruiting “economically inactive” people in the UK to do “low-skilled” jobs.

Rachel Harrison, GMB’s national officer, said: “Care in the UK is facing almost a 500,000-person black hole thanks to the government’s insulting immigration policy and failure to properly fund the sector. For the likes of the home secretary to brand the care workers our whole society relies on as ‘low-skilled’ is a bit rich and has caused stress and anxiety for people who do an outstanding job day in, day out.”

The Migration Advisory Committee said earlier this year that the new earnings threshold would “increase pressure on social care [and] raise the dependency ratio”. It added that “the very real problems in this sector are caused by a failure to offer competitive terms and conditions, something that is itself caused by a failure to have a sustainable funding model”.

Harrison said: “For too long, care workers have faced inadequate rates of pay, lack of recognition for their skills and denial of opportunities for progression. We are determined to defend our members of all nationalities when their jobs are under threat. The demand on social care services is increasing every day, workloads are already unmanageable and the government has no plan for filling the black hole of almost half a million workers that could result from their policy. At a time when our care system is facing its greatest-ever crisis, this government seems determined to hack away at its greatest asset – our carers.”

The Home Office said: “The Migration Advisory Committee has been clear that immigration is not the solution to addressing staffing levels in the social care sector. Senior care workers who meet the criteria will still be able to come to the UK through the points-based system.

“We are working alongside employers to ensure the workforce has the right number of people to meet increasing demands and have recently launched a national recruitment campaign. We are also providing councils with access to an additional £1.5bn for adults and children’s social care in 2020-21.”