The man, a joint British-Afghan citizen, received an email from the Foreign Office on 23 August telling him to travel with his family to an evacuation centre where he would be “put on the next available flight”.
They followed the instructions and queued outside the Baron Hotel every day, but were not evacuated, and fled after a deadly bombing struck a nearby entrance to Kabul Airport.
Legal documents seen by The Independent say the family are now trapped in Afghanistan and living in hiding, and that “their lives are at real and immediate risk”.
An application lodged at the Administrative Court is seeking a judicial review of the government’s Afghan evacuation policy, alleging that it was not fair or reasonable, and that ministers then failed to take proper steps to assist those left behind.
Nina Kamp, of law firm Duncan Lewis which is representing the family, said: “Our clients were, through no fault of their own, left behind in August.
“They live in fear of the Taliban on account of their association with the UK. Now, the Home Office has made it impossible for them to apply for leave from Afghanistan, and even if they do make it to the UK, they will not be given the ‘warm welcome’ received by people who were evacuated in August, who all automatically received indefinite leave to remain,” Kamp continued, adding, “Instead, they will have to meet all the requirements of the immigration rules which may well be impossible for them.”
The case claims that anyone stranded now faces unreasonable hurdles and costs for reaching the UK safely, which were waived for their evacuated counterparts.
They have to pay fees for entry clearance applications, which are £1,523 per dependent child and partner, and lawyers say it is impossible to comply with requirements because there is no visa application centre in Afghanistan and necessary biometric information cannot be taken in the country.
Other requirements include an English language test, and certain levels of income or savings.
The legal challenge claims the policy “unlawfully discriminates” between people who were called forward by the British government for evacuation, but did not get a seat on a plane, and those who did.
It warns that the family, and others like them, will have no choice but to make dangerous irregular journeys towards Britain if their situation does not change.
If the challenge succeeds, it could affect the treatment of all British nationals and dependents of who are currently unable to escape Afghanistan.
The case has been lodged against the Home Office, Foreign Office (FCDO) and Ministry of Defence (MOD), because the departments were each responsible for different aspects of the policy.
Lawyers representing the family are awaiting a response to the claim, and the Administrative Court will then decide whether to grant permission for a full judicial review.
The government has pledged to offer up to 20,000 Afghans sanctuary in the UK through a new resettlement scheme, but it has not yet started more than three months after the Taliban takeover.