Care workers from countries such as India, Nigeria and the Philippines who faced losing their immigration status in the UK if they left their employers have been promised new protections by a landmark, grassroots deal.

The migrant care workers charter is an agreement designed by care workers and the trade union Unison to prevent the exploitation of people on sponsored visas – and Salford council is the first in the country to sign up to it.

The immigration status of people on post-Brexit sponsored health and care worker visas and skilled worker visas rests on them having a licensed employer. If they lose their job, the Home Office can cancel their visa, giving them 60 days to find a new sponsoring employer, apply for a different visa, or leave the country.

Union organisers say this means care workers who have sold everything to come to the UK, often to work with people with dementia or complex needs, are vulnerable to exploitation by under-scrutinised employers.

The charter includes a commitment that signatories, such as Salford council, will identify or act as an ‘‘employer of last resort” for care workers who have been victimised, or whose migration status is jeopardised after losing a job through no fault of their own, helping them to stay in the UK. Signatories also commit to creating an “ethical recruiter list” to stop rogue employers getting public money.

It comes after discoveries made over the last year by union officials in Greater Manchester.

In one case, Nigerian workers at a care home in Salford faced losing their status in the UK because the home was closing and its site being sold for development, before Unison helped them find new jobs and secure unpaid wages. The union has also been working with Nigerian care workers employed by agencies whose licences were withdrawn by the Home Office.

Officials helped dozens of Indian care workers who had raised concerns about underpayment and conditions, and felt their immigration status was being used to threaten them, which their employers deny. They organised midnight meetings to accommodate their long working hours before securing union recognition.

Steve North, the Unison president, said the situation faced by some care workers in the UK brought to mind the “Kafala” system in parts of the Middle East. “You are completely owned by the company you work for, they control your destiny and that of your family, and if you don’t do as you’re told you risk deportation, so you do what you’re told,” he said.

Idris Kauji, 44, of Preston, an Indian care worker who helped shape the charter, told the Guardian the precariousness faced by employees on sponsored visas was the “biggest issue in adult social care”.

Matthew Dickinson, a local organiser for Unison who helped care workers from overseas in Salford, said workers were being “duped, paying in some cases £25k” to recruiters before arriving to find there was no work for them, or they were made to work unpaid for long periods.

While the process began in Greater Manchester, the charter has been shaped by care workers from across the UK, such as Lorato, 38, who came to south-west England on a sponsored visa from Botswana in 2022 to work with disabled adults. She was promised her own accommodation by an employer, but found herself sharing a room with another woman in a two-bedroom flat accommodating seven people.

“I didn’t feel safe,” she said. “I had to fight for my salary, and then my employer was raided by immigration. Only now do I feel like I’ve reached England, because my new job is properly paid.”

Salford’s elected mayor, Paul Dennett, said it was an honour to be the first signatory to a charter that was a “thorough step” towards tackling examples of persecution and victimisation that care workers from overseas were “experiencing far too frequently”.

He added: “I hope many other local authorities across the country, especially Labour-controlled ones who have a historic responsibility to work hand in hand with trade unions, commit to [it] just as we have, and begin the fightback against the exploitative conditions in this sector, because ultimately, better conditions for care workers mean better standards of care for residents.”