UK immigration policy is leaving some immigrants struggling to remain here “riddled with anxiety” about whether they might not be able to renew their status, according to a leading charity.

The Joint Council for the Welfare of Immigrants (JCWI) also said the policy affects the mental health of people who are trying to come into the UK for family or business reasons.

The National has consistently highlighted cases where families already living here have been told to leave after rule changes were implemented retrospectively.

They include Gregg and Kathryn Brain and their son Lachlan, in Dingwall; Jason and Kirsty Zielsdorf and their five children, who returned to Canada last year after running the lifeline Laggan Stores for more than eight years; and Russell and Ellen Felber, who have lived in Inverness for more than five years where they run a successful bed and breakfast.

In an exclusive interview with The National, JCWI chief executive Satbir Singh said: “It’s affecting the health of people who are in the UK and struggling to remain here, or who are riddled with anxiety about the possibility of not being able to renew their status in the UK, or the risk that policy may change.

“It’s affecting the mental health of people who are not in the UK but who are trying to move here either for doing business which they might have set up in the UK and poured their life savings into, or to join family.

“In the case of families who are separated by migration law it obviously has a huge impact on the mental health of family members who are here, including children, and this is sadly one of the most neglected consequences of quite a restrictive and complex immigration system.”

Singh said their last study indicated that at least 15,000 children in the UK had been affected by changes to immigration rules, including financial and language requirements.

“Of those children who were surveyed, 79 per cent were suffering from distress and anxiety as a result of being separated from one of their parents,” he added.

“The symptoms ranged from nightmares to very severe depression [and] bed-wetting. For adults the effects are no less severe – mothers and fathers who are separated from their children [and] husbands and wives who are separated from each other.”

He said the cases tended to drag on for a considerable time and the mental health impacts grew over time. “It’s particularly concerning because at the last General Election the Prime Minister and the Conservative Party made mental health one of their priorities and very recently the Government announced the creation of a Minister for Loneliness.

“You don’t have to look very far to find evidence of loneliness and very severe mental health impact being forced upon people by a very short-sighted and very cruel immigration policy.”

Singh added that there was a side of the immigration debate that was not often heard – where people were making a positive contribution to their communities: “There are very real and vivid stories behind these numbers and so many of these people are making an incredibly positive contribution economically, to local communities. And the kind of difficulties they encounter … which are imposed on them by an out-of-touch immigration system doesn’t often enough take into account the humanity of those people and the links they have with their communities.

Drew Hendry, the SNP MP for Inverness, Nairn, Badenoch and Strathspey, told The National: “Whether it is the complicated nature of continuous changes, the months of uncertainty during the application process or lack of avenues to challenge decisions – one thing is clear that the Home Office does not consider the very real impact their policies have on people’s lives and wellbeing.

“It is time they ended their dogmatic approach and fully considered the human cost of their policies.

“In the case of my constituents the Felbers, of Inverness, I know that the uncertainty hanging over their future has had a very real impact on their health and I have requested an urgent meeting with the Immigration Minister to discuss the case.”

Singh also responded to the Government’s announcement that the NHS charge paid by migrants is to double from £200 to £400.

He said: “This is an outrageous and cynical attempt by the government to shift the blame for its own failure to deal with the crisis in the NHS. The health minister James O’Shaughnessy speaks about an NHS ‘paid for by British taxpayers’, ignoring the enormous net contribution of migrant taxpayers and of the migrant workforce that has helped keep the NHS running every day for 70 years. Of course, it’s right that we all contribute but this is a shameful attempt to stir up division and hatred by implying that migrants don’t already do so.”