Women with children, and smaller, regional businesses will be hardest hit by plans to slash immigration to the UK, according to trade groups and migration experts, who warn that aspects of the policy are likely to be challenged in the courts.

Rishi Sunak’s government on Monday set out measures to regain the political initiative by cutting inflows by 300,000 people a year, after official data showed net legal migration hit a record 745,000 in 2022.

The biggest surprise in the changes was a sharp increase — from £18,600 to £38,700 — in the minimum salary that British citizens or migrants already settled in the UK must earn in order for immediate relatives to join them.

This doubling of the earnings threshold will make very little difference to the overall level of net migration; unpublished Home Office estimates put the reduction “in the low tens of thousands”.

But experts warned it would wreak havoc on the personal lives of those affected and hit women disproportionately.

Madeleine Sumption, director of Oxford university’s Migration Observatory think-tank, said the change would hit women harder as they earned less on average than men and were more likely to work part-time.

Three-quarters of women in UK employment earned below the threshold, Sumption said. But mothers of young children who wanted to return to the UK after living abroad could find themselves in an even tougher position, she added, because the Home Office under current practice does not take into account the prospective earnings of a non-UK citizen not yet in the country.

Writing on X, Colin Yeo, a barrister and founder of Free Movement, an immigration law website, said that the change would “destroy many lives”, adding: “It’s particularly punishing to those outside London, minority communities and British citizens returning from abroad.”

Brian Bell, chair of the government’s Migration Advisory Committee, said ministers would need to justify why they had changed the formula used to set a minimum wage threshold for the family visa route.

He added that it would be “surprising if there wasn’t a legal challenge”.

The change to the UK’s regime for family reunion — already one of the most stringent in the advanced world — is in keeping with the new ban on care workers bringing dependants.

This will have a much bigger effect on the numbers coming to the UK, cutting net migration by about 120,000 a year, according to Home Office estimates, in addition to an expected reduction of 140,000 owing to the ban announced this year on masters students in the UK bringing relatives.

Ministers have said the chronically understaffed care sector will continue to be able to hire, because it is exempt from the minimum salary requirement of £38,700 for skilled workers, and can draw on a global pool of people without family ties who are still willing to do the jobs.

But Sumption, who also sits on the MAC, warned that care employers, who had been hiring qualified nurses from overseas to fill entry-level roles, might struggle in future to attract applications from such highly skilled candidates.

Restricting dependants could also “make care workers in the UK more isolated”, she said, depriving them of the support from a partner “that can help workers to escape exploitative situations”.

Meanwhile, business groups accused ministers of hypocrisy for expecting private-sector employers to pay higher wages and immigration charges, while exempting state-funded sectors from the salary requirements.

Neil Carberry, chief executive of the Recruitment & Employment Confederation, said: “One rule for business, another for the public sector in health and care will not go down well with those in industry.”

Business groups said the higher salary thresholds for skilled workers would worsen chronic labour shortages in some crucial areas, while making very little difference to net migration.

The Home Office estimates that the pay thresholds will reduce annual inflows by 14,000. This would barely dent the latest figure of 672,000 for overall net migration.

It would, however, be a significant cut to the number of skilled-worker visas granted outside the health and care sectors, which totalled 66,322 in the year to September, with a further 50,874 dependants accompanying them.

Top City of London employers offering high salaries will be largely unaffected. But the thresholds will pose a big problem for small regional businesses — already deterred by Home Office visa fees and charges — in sectors where employers have been struggling to fill critical positions. 

“Small and medium-sized enterprises will undoubtedly be priced out of the market — they simply won’t be able to sponsor workers in critical roles,” said Chetal Patel, head of immigration at law firm Bates Wells.

Many employers will be hoping that the MAC’s promised review of the “shortage occupation list” — which offers easier visa terms for certain roles where the UK lacks homegrown workers — will allow them to continue hiring overseas staff in some lower-paid sectors.

Construction, hospitality, butchery and manufacturing are all areas where employers have used the visa system more freely since Brexit, as the supply of EU workers has dried up. Unless they secure some form of exemption from the new rules, use of the visa system is likely to become impossible.

Kate Nicholls, chief executive of trade body UKHospitality, said “around 95 per cent” of the 8,500 workers in the sector granted visas last year, including those for “talented chefs and managers of the future”, would not be eligible under the government’s proposed regime. 

“These changes will further shrink the talent pool that the entire economy will be recruiting from, and only worsen the shortages hospitality businesses are facing,” she said. 

Jamie Cater, senior policy manager at Make UK, said many of the manufacturing group’s members relied on the visa scheme to fill highly skilled technical roles, including in welding and electroplating, that were usually paid below the £38,700 threshold.

Manufacturers did not see hiring outside the UK as an easy way to avoid training UK workers, he said, adding: “They use the immigration system as the last resort.”

The Home Office has been contacted for comment.