Key details of the UK’s post-Brexit immigration policy – including the salary threshold for migrants – will not be known until 2020 after cabinet infighting, it has been revealed.

Ministers will publish a long-awaited immigration bill on Thursday, to end free movement of EU citizens, but rows have delayed decisions until long after the UK leaves the EU.

It means businesses, the NHS and other employers will be in the dark about the minimum salary requirement for workers to obtain a long-term visa – which had been expected to be set at £30,000.

After a revolt led by Philip Hammond, the chancellor, and Greg Clark, the business secretary, no figure will be announced until 2020 – just months before the post-Brexit immigration system is due to start, in January 2021.

An “extensive 12-month programme of engagement” is planned with worried businesses, the NHS and local government leaders, who have already criticised the immigration clampdown.

Other deferred decisions include what benefits EU citizens will be entitled to, whether the pensions of British expats will be uprated and new rules for students.

The Home Office is also conceding that “similar numbers” of low-skilled EU workers could still come to the UK, despite a requirement for them to secure temporary visas of no more than 12 months.

They would be required to leave after a year and be barred from claiming benefits, bringing in family members or taking out a second visa until after a 12-month “cooling-off period”.

However, The Independent understands Home Office officials believe that – until employers have had time to “reduce their reliance on migrant labour”, with a review after five years – the numbers of migrants may remain at a similar level.

They would also be able to “switch” to other visas, such as study or tourism, and it is unclear whether they would have to leave the country to do so.

Earlier on Wednesday, Sajid Javid, the home secretary, confirmed his white paper, being published on Wednesday, omitted the discredited pledge to bring down net migration to “tens of thousands”, saying: “There is no specific target.”

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Mr Javid said he “go away and listen to what businesses have to say” – a process which, his white paper reveals, will take 12 months, starting early in 2019.

“We are not setting the exact threshold today,” he told BBC Radio 4’s Today programme, adding: “We will consult further on whether its £30,000 or thereabouts.”

The NHS has pointed out that doctors and nurses routinely earn less than a limit of £30,000, fearing such a regime could trigger a staffing crisis.

Saffron Cordery, the deputy chief executive of NHS Providers, which represents NHS trusts: “We are deeply concerned about what is going to happen. High skills does not equal high pay.

“You have got starting salaries for nurses at £23,000 – also for paramedics, midwives. Junior doctors starting salaries at £27,000, healthcare assistants at £17,000, all coming in way below that £30,000 cap.