Boris Johnson fails to say when pledge to scrap NHS fees for foreign staff will come into force

'These are people on the frontline. The prime minister said he would act – when is he going to do so?'

Boris Johnson has failed to say when his promise to scrap NHS fees paid by foreign health and care workers will come into force – almost one month after it was announced.

At prime minister’s questions, Keir Starmer demanded an explanation for the delay, saying: “These are people on the frontline. The prime minister said he would act – when is he going to do so?”

In response, Mr Johnson said only: “We are getting on with instituting the new arrangements as fast as we possibly can.”

The clash came four weeks after the prime minister agreed to scrap the immigration health surcharge for health staff, amid growing anger after The Independent revealed Priti Patel’s phony “review” of the controversy.

This week, it was revealed that hundreds of doctors are still being charged the £400 annual fee, a sum due to soar from to £624 from this October.

Staff applying for new visas say officials have told them they cannot guarantee fees paid now will be refunded, while others are being told the exemption will not apply to their immediate families.

There is also confusion over whether the fees will only be scrapped people renewing from within the UK, doctors say.

Yet, when Mr Johnson was forced into his U-turn on 21 May, Downing Street said he had told health officials to scrap the surcharge “as soon as possible”.

In the Commons, Sir Keir protested that “nothing has happened" in the month since the prime minister announced it would be dropped.

He highlighted the case of one doctor who has paid £6,000 to cover his wife, four children and himself.

On Monday, Dr Dolin Bhagawati, of Doctors' Association UK, said: “These workers are paying up to four times over for the NHS – through their service, taxes, this surcharge and, in some tragic cases, with their lives.

“It is not too much to ask that this government does the honourable thing: stop this extortion and scrap this charge as soon as possible for NHS and care workers as well as for their dependants.”

In the Commons,Mr Johnson said: “It is vital people who are working on the front line and NHS workers in particular get the support they need.

"That's why I said what I said a few weeks ago and what I can tell him is NHS or care workers who have paid the surcharge since May 21 will be refunded.”

Because the surcharge is also paid by spouses and children, the total cost can reach a crippling £8,000 for a family of four on a five-year work permit, or with limited leave to remain in the UK.

And it will be extended to all EU citizens from next January, if the Brexit process is completed by ending the transition period.

It cannot be deferred, or paid annually, but is demanded in advance for the entire duration of an applicant’s visa or residency permit.