More than 100 guards at the British embassy in Kabul have been told they are not eligible for UK government protection because they were hired through an outsourced contractor, the Guardian has learned.

Most of the 125-strong team of security personnel, employed by the global security firm GardaWorld, have been given informal notice that they no longer have jobs guarding the embassy, several said.

The guards, some of whom had been working for the UK embassy for over a decade, described feeling abandoned by British officials and their employer. Many have been forced into hiding, fearing for their lives.

Meanwhile, more than 100 guards doing the same work for the US embassy, under a separate GardaWorld contract, have been evacuated and others were receiving support from the US embassy, according to a senior Afghan national GardaWorld employee in charge of human resources.

On Saturday night, at the end of a long shift helping British diplomats get to Kabul airport so they could flee after the fall of the Afghan capital to the Taliban, several British embassy guards said they were told by phone that since the embassy was now closed their services would no longer be required. They were asked to hand back computers, body armour and radios.

One guard said he was told by a British expat GardaWorld operations manager on Friday that his contract was going to be terminated. “He said: ‘There won’t be a GardaWorld project any more with the embassy; your jobs are gone.’ He himself left Afghanistan the following morning … No one asked whether we are safe or not. No one asked whether our lives are in danger or not.”

Oliver Westmacott, the president of GardaWorld’s Middle East operations, said formal termination letters had not been sent out but added: “The reality is on Saturday when the contract was demobilised, we sent people home. We are going to honour people’s salaries, certainly up until the date that they stopped working, and we have every intention of giving people a final gratuity payment or severance.

“We need to get agreement from our clients, namely the British Foreign Office, as to what the notice period is going to be, otherwise we are materially out of pocket.” On Thursday night one guard said they had been informed their pay would continue for now.

Nearly all 160 GardaWorld employees working on the British embassy contract applied for help from the Ministry of Defence-run Afghan relocations and assistance policy (Arap), designed to assist people working for UK organisations, and all except 21 translators were rejected last month. They received letters explaining they were not eligible because they “were not directly employed by her majesty’s government”. “We realise this will be disappointing news,” the letters said.

The GardaWorld team provided all the security for the British embassy in Afghanistan under its “British embassy Kabul project”, including offices, accommodation and off-site visits. Most of the guards are men, but about 10 are women, responsible among other things for frisking female visitors to the embassy. Security for all British embassies globally was outsourced decades ago.

A GardaWorld HR manager said he was asked to prepare termination letters for many of the Kabul embassy guards last week but the process was disrupted by the arrival of the Taliban.

The guards, four of whom gave detailed telephone interviews to the Guardian, are hoping the UK government will reconsider its decision to refuse their applications for Arap.

“We have been doing a very dangerous job for the British embassy, and we are in a terrible condition. We are known as British embassy staff; our lives are now at risk,” one guard said. Another added: “We worked in frontline positions, doing the most dangerous work to keep British officials safe. We risked our lives for them, and now we find ourselves in this bad situation – not just us, but our families are at risk.”

The guards have written to the UK government asking to be included on the relocation list. “Contractors are human too; think of them as human,” they wrote, saying their jobs were “exposed and in the public eye” and they were sceptical about Taliban promises of an amnesty for people who worked for foreign organisations.

The UK rejection has been compounded by the apparent termination of their contracts, which has left many worried about how they are going to support their families.

Several former guards have spent the past three days queueing outside the Kabul airport in the hope they can talk to the small team of British officials still administering the evacuation schemes inside.

GardaWorld describes itself as the world’s largest international diplomatic security provider in high threat and complex environments. It also provides security for the British embassy in Baghdad, and embassy security services for more than 40 countries.

Asked if the embassy guards were still GardaWorld employees, Westmacott said: “Technically they are because we haven’t communicated with them formally to the contrary. … I fully appreciate the predicament that all these poor people of ours are in, in desperate situations trying to sort their lives out and get to safety. So, it is a nightmare. We fully recognise that.”

He said he has been working with the industry body, Security in Complex Environments Group, to try to help the guards.

The Ministry of Defence said the guards were welcome to reapply for the relocation scheme. A spokesperson said: “Nobody’s life should be put at risk because they supported the UK government in Afghanistan. Over the last few weeks alone more than 2,000 Afghan staff and family members have been relocated to start their new lives in the UK.

“We have significantly expanded and accelerated the relocation scheme and carefully assess each applicant for eligibility and security. Those who were dismissed for serious offences, including those that constitute a crime in the UK or threatened the safety and security of British troops, will continue to be excluded.”

The Foreign Office has been contacted for comment.