Campaigners have called on the government to make it easier for Afghans who worked with the British military to be resettled in the UK.
The main resettlement scheme is restricted to those deemed at significant enough risk, such as interpreters and translators.
However, it does not cover jobs such as mechanics, chefs and drivers.
The Sulha Alliance charity said such individuals were also at risk of attacks by the Taliban.
Under the Afghan Relocations and Assistance Policy (ARAP) scheme, Afghan citizens who worked with the UK government in “exposed or meaningful roles” may be eligible to be relocated to the UK, along with their family members.
The Sulha Alliance – which supports Afghans who worked for the British Army – has given evidence to MPs on Parliament’s Foreign Affairs Select Committee, which is looking at the government’s response to the UK withdrawal from Afghanistan in 2021 after the country fell to the Taliban.
Documents sent to MPs on the committee include the story of a 35-year-old former mechanic who worked with the British military in Afghanistan – and was refused resettlement by the UK government under the ARAP scheme.
The Sulha Alliance says that last month, members of the Taliban found his 87-year-old father and demanded to know where his son was hiding.
They say he refused to tell them and was beaten to death.
The evidence claims that before he died in hospital, he said the Taliban had told him they would kill him because his son was a “traitor” for working with the West.
The documents were submitted ahead of an appearance by Foreign Office Minister Lord Ahmad before the Foreign Affairs Select Committee later.
Peter Gordon-Finlayson, a former army captain who co-founded the Sulha Alliance, said he was concerned about how the government is assessing the levels of risk involved for Afghans wishing to be resettled in the UK.
He said the government argues that Afghans working in roles other than interpreters were not on the ground with British troops and so were not directly seen by the Taliban and the local community as working alongside the UK, putting them at less risk.
“Unfortunately that is not quite true,” he told the BBC.
“The reality is that those who were recruited to be mechanics and chefs and so on and support the British Army, were recruited locally from the areas around where the British military camps were – and so they were known within the community – and they were seen every day going in and out of British army bases, so they are very much at risk.”
It is understood the government has indicated to campaigners there are no plans to change the ARAP scheme to include more professions.
Mr Gordon-Finlayson said if the government would not change the ARAP scheme, they should adapt other schemes to make it easier for people like the mechanic highlighted by the Sulha Alliance to be resettled in the UK.
The government runs a second scheme for vulnerable Afghan refugees known as the Afghan Citizens’ Resettlement Scheme (ACRS) – but at the moment the only way to apply is through a recommendation from one of a number of specific organisations such as the UNHCR, the UN Refugee Agency.
Mr Gordon-Finlayson said: “We’d like to see a scheme where individuals can apply directly to that pathway to be able to be brought to the UK in a safe and legal way.
“Those who worked with us are now in hiding permanently, not able to work, therefore not able to support their families and that also plays havoc with mental health,” he said.
“So there’s a lot of desperate people out there who are feeling very isolated and like their service to the UK was the worst mistake that they could make for both them and their family.
“I fear for the next major military operation that we as a country embark upon, that we will struggle to recruit brave men and women from the local community to do these crucial role to support us.”
The charity’s evidence also raises concerns among campaigners about why some applications are taking so long.It believes some former interpreters are finding it difficult to have their resettlement confirmed because their contracts with British forces were previously terminated.
Mr Gordon-Finlayson said: “I know from my time in Afghanistan that interpreters had their employment terminated because of petty squabbles amongst the interpreters – who owned the TV in the interpreters’ tent – or something like that…
“Some people who were let go for reasons that were not genuine national security threats are now stuck in Afghanistan because of the way that their contract with the UK forces ended, and that strikes us as unfair.”
A government spokesperson said: “The UK has made an ambitious and generous commitment to help at-risk people in Afghanistan and, so far, we have brought around 24,600 people to safety, including thousands of people eligible for our Afghan schemes. “We continue to honour our commitments to bring eligible Afghans to the UK.”