When a Kenyan nurse took up a job in the UK a few years ago, he felt his family's future had been secured.
But now the distraught father-of-three is struggling financially to reunite his family.
Ken, not his real name, lives with his wife and daughter.
But his twin children, a boy and a girl, remain in Kenya where they live with relatives.
That's because Ken is unable to raise enough money to cover a British health tax, known as the immigration health surcharge (IHS).
'Struggling to stay afloat'
Migrant workers coming to the UK from outside the European Economic Area (EEA) and their dependents have to a pay an annual fee of £200 ($268) each.
Ken is also required to have £2,185 in his account for three months before he can apply to bring his twins into the country - on top of the £400 he will need for their health tax.
"It's very difficult to explain to them when they ask me when they will join me here.
"Ideally, every parent would love to be with all their children."
Top five nationalities of non-EEA NHS staff in England
- Indian - 18,348
- Filipino- 15,391
- Nigerian - 5,405
- Zimbabwean - 3,899
- Pakistani - 3,375
One in eight National Health Service (NHS) England staff are not British nationals, and people from a total of 201 foreign nationalities work for NHS England.
Source: House of Commons Library
The time difference and the nature of his job also make it difficult for him to give the twins the attention they need.
"Sometimes when you're at work, they call and you cannot speak with them as you'd love to, since you're really busy," he says.
The health surcharge was introduced in 2015 to boost funding for the National Health Service (NHS) and as a way to discourage health tourism.
Later this year, the annual charge is to be doubled from £200 to £400, with the discounted rate for students set to increase from £150 to £300.
If Ken does manage to bring his twins over to the UK, the annual health tax for the whole family in future will total £2,000.
He earns £1,800 a month after tax. But, once the bills and rent have been paid, he is left with only £500.
"The £500 is for food, transport and other needs, and can't satisfy my children's needs," says Ken.
"The IHS is causing families to separate and I don't feel we're being treated fairly," he says.
"I'm struggling to keep afloat."
At the annual conference for the Royal College of Nursing (RCN) last month, union members unanimously voted to demand that the government waive the fee on work permits for nurses and their dependents.
The union's resolution said it was "morally questionable" for foreign nurses "to pay the health surcharge, given that they pay national insurance and income taxes, as well as providing a vital service to the public".
For the nurses' union, recruiting and retaining qualified nurses is a major issue.
The NHS faced a shortage of nearly 88,000 workers between July and September 2017 in England alone, statistics from NHS Digital show.
"Nursing staff are increasingly caring for sicker patients with multiple long-term conditions," says Janet Davies, general secretary of the RCN.
"This demands safe staffing levels and the right specialist skills. Yet as patients get sicker, the number of nurses continues to decline, due to years of cost-cutting and poor workforce planning."
The government needs to address these shortages, especially as the UK has an ageing population, she says.
A patient's ability to recover is determined by the number of nurses on duty, she adds.
A double tax?
A Home Office spokesperson reiterated that the government was aware of the "contribution" made by international professionals "to the UK and to our health service".
But it said the surcharge offered access to healthcare that was "far more comprehensive and at a much lower cost than many other countries".
"The income generated goes directly to NHS services, helping to protect and sustain our world-class healthcare system for everyone who uses it," the spokesperson said.
But Ken says foreign nurses already pay income tax in the UK.
"I think it's an issue of double taxation, because once you've paid taxes you should enjoy these services," he says.
"You work so hard, do the nights and heavy 12-hour shifts helping the sick, but you end up feeling not supported and you can't help yourself."
Ken is considering leaving the UK if he is not able to raise the funds to bring over his twins, as the situation is causing him and his family a lot of stress.
"I have thought of going to other countries - Canada or maybe Australia - and starting the whole application afresh with everybody on board."