It’s children who will shoulder the caring burden under Johnson’s migration policies

As soon as Marissa was old enough to walk, she started caring for her mum, Suzanna, 51, who was left with severe spinal damage and arthritis on top of long-term breathing problems after two car accidents. The five-year-old helped her disabled mum to get to their third-floor flat in a block with no lift access; she would hold her mum’s hand as they went up, step by step – all 150 of them. Marissa would bring her water, do the laundry, and shuffle to reach the bottom supermarket shelves.

She would even try to help cook tea: dry pasta and tomatoes. “Marissa would say, ‘Mummy, you have a mouth full of hands, let me help’,” Suzanna says. “She meant ‘you’ve got your hands full’.”

Now 11, Marissa is only a few months into “big school” but is on call for her mum 24/7. Three years ago the council gave Suzanna an allowance for eight hours’ care a week from a personal assistant, but it’s nowhere near enough. Marissa picks up the slack, helping her mum get out of bed in the morning, and chips in with the washing up, cleaning, cooking and shopping.

Marissa is in every way a superstar – “she amazes me”, Suzanna says – but it’s easy to see she’s just a child. “I get upset sometimes because I go online and see all my friends are going to places that I want to go to,” she admits. “They [don’t tell me] about it because they know I can’t go.”

When Boris Johnson announced his new immigration plans last week – said by unions to spell “absolute disaster” – it’s unlikely he was thinking much about Marissa. Currently local government is scraping the bottom of its coffers, and there are 122,000 social care vacancies, meaning both social care packages and the staff needed to provide them are already scarce.

Who’s filling in the gaps? In part, young carers like Marissa. Figures suggest there’s 700,000 in the UK, though that’s likely to be the tip of the iceberg. Research by the charity Action for Children this month finds young carers are quietly doing the equivalent of £12,000 of unpaid work a year. “Young carers” is a tellingly sanitised term – a euphemism for child labour. We normalise it, accepting working conditions for children that would not be legal outside the home.

Now, even a break is too much to ask for. A decade of austerity means that not only have social care packages shrunk, but so have the budgets for respite centres. Services across the country designed to give kids a rest have closed their doors, while many run by charities like Action for Children have been taken back in-house by councils and run as a skeleton services – often with no transport or outreach capacity for hard-to-reach families.

Child carers are not an anomaly of the social care crisis but a grotesque example of a bigger scandal, one where the state withdraws responsibility and the burden falls on already struggling families.

In new research by the MS Society, one in six family carers say they are now providing over 90 hours of care every week as cash-strapped local authorities withdraw provision. For their trouble, the government provides £66.15 carer’s allowance a week. Their reward? A higher chance of living in poverty and with mental and physical health problems from the toll of caring. The MS Society study shows a third of respondents have had to give up work to care for a loved one – and these are largely women.

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If the human impact isn’t enough, consider the economic case. Research shows that unpaid carers giving up work early to provide this support costs between £3bn and £6bn in lost tax every year in England. Migrant care workers are a lifeline for a service that is flatlining – four in 10 care workers in London are from overseas – and yet Johnson’s dog-whistle immigration plans dare to call them “unskilled”. The solution of the home secretary, Priti Patel, to replace migrant workers with “economically inactive” people, turned out to be largely made up of the long-term ill: those who retired, and – you guessed it, those already taking on unpaid caring responsibilities.

Ministers have long tried to shift the social care burden on to families. In 2018, they launched the “big society” initiative as bankrupt councils were told to lean on relatives and neighbours in order to meet their legal duty to disabled and older people. Get ready for more of this rhetoric in the coming months as the government finds out what “taking control” really means for the crumbling care sector.

But the case for immigration cannot be made by weighing up what migrants can do for the rest of us. The demands for both a humane immigration and social care system come down to the same point: we are human beings with intrinsic worth, who deserve dignity and respect.

It is only by valuing caring labour that ministers will provide what it needs: real investment in social care, support for family carers and a more welcoming attitude toward migration. When children are left to clear up the state’s mess, the government has truly failed.

• Frances Ryan is a Guardian columnist