That is the reality for an estimated 1.4 million people in the UK whose visa conditions give them no recourse to public funds (NRPF).

On a wintry day in east London, a queue of people stretches a hundred metres or so down the road.

Huddled against the cold, they wait their turn to access a food bank, run by the Newham Community Project, specifically for those with no recourse to public funds.

NRPF is attached to a variety of student, family and work visas, and means the individual cannot access support such as universal credit, child benefit, and some recently announced cost of living support schemes - although others, such as help with energy bills, were made universally available.

The number of people using the service has doubled in the last few months alone.

"Being a mother, I feel very upset because I have to choose from putting the heating on or putting food on the plate," said one woman in the queue.

"Costs are rising. Everything me and my husband earn goes towards rent and bills. After that, there's nothing left."

'They can't afford day-to-day expenses'

Chief executive Elyas Ismail said his service is struggling to cope with the demand.

"It's heartbreaking," he said. "It's worse for them because they don't get any help. They're on their own. Many of them have two jobs, and even then they're not able to afford normal day-to-day expenses."

This month, a report by the Food Foundation and the University of Hertfordshire found that not only were NRPF families struggling to access healthy food, but that they were struggling to access a sufficient amount of any food whatsoever, with "devastating effects on quality of life".

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The government defends the system on the basis that it expects migrants to be able to support themselves and their families without relying on benefits.

It says that should anyone face sudden hardship, "strong and important safeguards are in place to ensure the vulnerable can receive support".

Those safeguards, known as "change of conditions" applications, allow people to apply to access public funds in an emergency.

However, the process is complex, often little understood, and takes time: a luxury that many simply don't have.

'It makes you feel almost useless'

One young mother spoke to Sky News on condition of anonymity.

She and her two-year-old daughter recently became homeless whilst awaiting a change of conditions decision.

Her daughter is a British citizen, through the father, but he is no longer around, and the mother cannot claim child benefit to support them.

"It makes you feel almost useless, like you can't provide for your child," she said.

"You have nowhere to turn to, and you can't get the help you need right away. Getting a change of condition is not something that happens overnight, and when you need that help now, there's just no one that can initially help you."

One organisation that helps people with change of conditions applications is the Unity Project.

Co-founder Caz Hattam says the system needs to change.

"The average amount of time an application takes is six weeks, which is a huge amount of time to be waiting, but we've seen applications take months and even over a year to decide.

"It means that people have to go through a very long and gruelling application process before they can access the most basic support."

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Earlier this year, the cross-party House of Commons work and pensions committee called for reform, including by reducing waiting times and making child benefit available to all parents of British children.

So far, the government has resisted such calls.

The Home Office said in a statement: "The provision of No Recourse to Public Funds has been upheld by successive governments and maintains that those coming to the UK should do so on a basis that prevents burdens on the taxpayer."