As part of the “hostile environment” strategy, launched in 2012 under former home secretary Theresa May, authorities have overseen a four-fold increase in visits to mosques, temples and churches since 2019 with the aim of targeting illegal immigrants.

The strategy was launched to make staying in the UK illegally as difficult as possible, with the government encouraging people to leave the country voluntarily.

In at least three cases this year, immigration authorities — the Home Office’s National Community Engagement Team — directly escorted people from religious sites to airports and aboard flights leaving the country.

The department carried out more than 400 visits to religious centers over the past three years, targeting illegal migrants and failed asylum-seekers.

A freedom of information request by The Independent shows the dramatic increase in the number of visits each year.

In 2019, 46 took place, compared with 167 in 2021. From January to July this year, 137 visits had already been carried out, suggesting that the end-of-year figures could represent a record high.

Home Office guidelines on the visits say: “Some communities, as well as faith communities, may be unwilling to assist police/immigration in carrying out operations. Reasonable steps must be taken to seek advice from the communities concerned.

“You must ensure and provide evidence that all other avenues of investigation have been exhausted. Scheduling a religious premises operation should be the last resort.

“This sensitive type of operation will involve large numbers of police officers, intelligence officers and, in some instances, offenders.

“Operations at religious premises must be authorized at deputy director level and the minister for immigration must be informed. Such sensitive cases may require the home secretary to be informed.”

Policy adviser for the Joint Council for the Welfare of Immigrants Mary Atkinson criticized the practice.

“Immigration enforcement has no place in faith spaces — the government must immediately stop running these workshops and scrap the hostile environment so that everybody can access essential public services,” she said.

“Faith spaces of all kinds are essential places for reflection, community and spirituality.

“They are often even more important for migrants who, because of this government’s anti-migrant obsession, face discrimination and are barred from the most essential services.

“That’s why it’s so shocking to see the Home Office breaching the sanctity of these spaces and using them to pursue worshippers.”

Shakila Taranum Maan, of domestic abuse charity Southall Black Sisters, said: “Many of our clients are being duped and misinformed about what these surgeries are for.

“We’ve spoken to people who thought they were going along to get help, but instead they are being advised it’s better to leave the UK and they’re told, ‘this is how much you’ll be given.’

“The Home Office officials aren’t identified clearly enough, so people are giving out all their personal information, not knowing who they are giving these details to.

“Our clients feel this is a violation of the grounds of worship — people go there because they are in turmoil, to search and look for peace. People often go there for food at the community kitchen.”

A Home Office spokesperson said: “Our community engagement surgeries allow people to seek information from immigration officials on their stay in the UK or receive practical support to return home voluntarily.

“These surgeries are conducted with the permission of community leaders, and are held in conjunction with faith-based and community locations in order to have conversations with individuals without the fear of arrest.

“These are clearly advertised as government-run, and officials identify themselves as being government employees.”