The UK abandoned its supporters in Afghanistan and left them at the mercy of the Taliban, according to a whistleblower.
A former Foreign Office worker has slammed the UK's evacuation efforts from Kabul airport as the Taliban seized power in August.
Speaking to a parliamentary committee, Raphael Marshall said thousands of pleas for help were left unread.
In devastating evidence, Marshall estimated that just 5% of Afghan nationals who applied to flee the country under one UK programme actually received help.
He told the committee that thousands of emails were left unread between August 21 and August 25, and at one stage, he was the only person monitoring the inbox.
"These emails were desperate and urgent," he wrote to the Foreign Affairs Select Committee. "I was struck by many titles including phrases such as ‘please save my children’.”
As the Taliban surged through Afghanistan, the UK, US, and other Western countries rushed to evacuate Afghan allies who had worked with them, at risk of violent reprisals.
Britain managed to airlift 15,000 people out of the country in two weeks, and the government says it has since helped more than 3,000 others leave Afghanistan.
But an Afghan Resettlement Scheme -- aiming to bring another 20,000 people to the UK after August -- has yet to get underway.
Marshall -- who left his post at the Foreign Office in September -- said some of those left behind have been killed by the Taliban.
The Foreign Affairs Select Committee was appointed to investigate the country's "dysfunctional and chaotic" departure from Afghanistan.
Tom Tugendhat, a Conservative MP who heads the committee, said Marshall’s testimony “raises serious questions about the leadership of the Foreign Office".
British Deputy Prime Minister and former Foreign Secretary Dominic Raab has defended his actions.
Speaking to the BBC, Raab admitted that there were "lessons to be learned", but insists he did "a good job" when compared to other international efforts.
Raab had previously faced criticism for being on holiday in Crete as the Taliban began seizing cities across Afghanistan.
The committee is due to question senior Foreign Office civil servants later on Tuesday.