From 6 April all skilled workers from outside the EU who have been living here for less than 10 years will need to earn at least £35,000 a year to settle permanently in the UK. Some jobs, such as nurses, are exempt (see How the rules are changing, right) but Frazier’s is not. Unless she gets a higher-paid job, she will be deported in September.

“I’ve chosen to take a lower salary because I’m trying to improve the lives of unaccompanied child refugees and do good in the world through music and education,” she says. “How do you put that on paper in a visa application? How do you show the value of trying to make a child’s life better?”

A petition to scrap the £35,000 threshold has attracted more than 100,000 signatures from British citizens and was debated in parliament on Monday. “I started the petition because I don’t want to live in a Britain that will quietly usher thousands of people out of the country without raising a whisper of protest,” says Josh Harbord, the British citizen behind the Stop35k campaign which has attracted the support of SNP, Labour and Green MPs. “I don’t want to live in a country that values people’s incomes over people’s contributions to society.”

But the government is adamant that the policy is fair, and that individuals have had many years to prepare.

A Home Office spokesman said: “In the past it has been too easy for some businesses to bring in workers from overseas rather than to take the long-term decision to train our workforce here at home.

“We need to do more to change that, which means reducing the demand for migrant labour. That is why we commissioned the Migration Advisory Committee to provide advice on significantly reducing economic migration from outside the EU. These reforms will ensure that businesses are able to attract the skilled migrants they need, but we also want them to get far better at recruiting and training UK workers first.”

Home secretary Theresa May was criticised for failing to attend the debate in person, instead sending a junior minister with an unrelated portfolio – Richard Harrington, minister for Syrian refugees – to defend the policy.

In its own impact assessment, the Home Office estimates the new salary threshold will cost the British economy between £181m and £171m (PDF), while the other organisations have put the cost much higher, at £761m (PDF).

“These new rules will damage the British economy, our standing overseas, and our society as a whole,” says Ralph Buckle, co-founder of the Commonwealth Exchange. “We have already seen dramatic falls in Commonwealth migration to the UK due to existing restrictions and the salary restrictions will only make things worse.”

Latest Home Office statistics show there were just over 55,000 applications for skilled work visas in the year to March 2015. Americans were among the largest groups – 12% of applications – while Australians made up a further 4%.

The government’s own admission that the reforms will only make a “modest” contribution to its target of reducing net migration was repeatedly highlighted during the debate: “The word ‘bonkers’ springs to mind,” said Stuart McDonald, an SNP MP. “If the so-called gain is a modest one, why inflict so much pain?”

Gillian Brown, 26, is one of the Australians at the receiving end of that pain. Her entire family decided to emigrate to the UK when she was 18 but, due to her age, she could only enter the country on a student visa (while her younger brothers were classed as dependents and are now full British citizens). She graduated with a first class BA and an MA from The University of Sheffield, and currently earns £20,300 as an online marketing assistant after moving into a skilled workers’ Tier 2 visa in 2014.

“Previously, I’d have been able to apply for permanent residence in the UK after five years, earning my current salary. Not any more,” says Brown. “It’s a constant worry. If I can’t convince a company to sponsor me again next year, I’ll be deported back to Australia after eight years in the UK, and separated from my parents and brothers. But the British government doesn’t care about separating families – they’ve made that very clear. ”

Australian migration specialists True Blue say the new rules have caused a spike in the number of British-based Aussies looking to head back home. In the last week of January, it saw a 50% increase in calls seeking advice on how to secure their British partners a visa in Australia.

Walkabout, the Australian bar chain, has already begun stepping up its recruitment strategies to try to deal with any fallout from the visa restrictions. “We have been losing Australian staff for some time,” says Nina Marshall, HR director. “Recruiting Australians is essential to the authenticity of our brand and this challenge is only going to become significantly more difficult.”

Jeffries Briginshaw, CEO of BritishAmerican Business, is also concerned: “American companies are deeply entrenched in the UK economy and American citizens are part of UK society, whether this is in business, schools or families. Any restriction to the Tier 2 visa scheme will have a negative impact on the way American businesses operate in the UK and how American citizens can be part of the UK.”

It’s not only business leaders who are against the change. “Migrant teachers make a significant contribution to the UK,” says Kevin Courtney of the National Union of Teachers. “It seems absurdly counterproductive to force schools to dismiss migrant teachers they’ve trained and invested in, and who are still very much needed, at a time when highly skilled, qualified teachers are in great demand. The policy urgently needs to be reconsidered.”

How the rules have changed:

To enter or stay in the UK as a skilled worker, non-EU migrants must have a Tier 2 visa. To qualify, one must have been offered a job in the UK and have held at least 945 pounds in the bank account for 90 days.

The job a prospective migrant is offered must pay at least 20,800 pounds, although the British government is currently considering a recommendation to raise the amount to 30,000 pounds. Certain occupations do not have to meet this threshold.

Individuals must also get a certificate of sponsorship from the employer and pay 200 pounds per year as a healthcare surcharge and should be able to prove their knowledge of the English language.

Non-EU migrants are only permitted to remain in the UK on Tier 2 visas for a maximum of six years.

However, at the moment, skilled workers who have been living in UK on these visas for five years are able to apply for “indefinite leave to remain” in the UK, this rule is about to be changed.

From April 6, only those who earn 35,000 pounds a year will be eligible to apply for “indefinite leave to remain” once they have lived in the UK for five years.