A new report has revealed 1,500 Afghan staff who worked for the UK Government were called forward to Kabul airport but not evacuated during Operation Pitting.
The cross-party Foreign Affairs Committee, led by senior Tory MP Tom Tugendhat, concluded that the withdrawal was a "disaster" and a "betrayal" of British allies that will damage the UK's interests for years.
The committee said "mismanagement... of the evacuation effort in a crucial period likely cost hundreds of people their chance to leave the country, and as a result likely cost lives".
Ed Aitken, a former Army officer who served in Afghanistan's Helmand Province, is the co-founder of the Sulha Alliance – which helps Afghan interpreters get out of the country
He told Forces News the Afghan Relocations and Assistance Policy (ARAP) scheme told former Afghan staff they "must go and get… travel documents" from the Taliban.
"If they turned up to the government ministries, run by the Taliban, that are now issuing passports, of course they have names and lists of all these individuals who worked for the international security forces," Mr Aitken said.
"And therefore, they would be arrested."
Watch: Former Afghan staff need more help to reach safety, former interpreter says.
The hasty efforts to select individuals for airlift was "poorly devised, managed and staffed", with a lack of clarity causing "confusion and false hope among our Afghan partners who were desperate for rescue", according to the report.
"They, and the many civil servants and soldiers working hard on the evacuation, were utterly let down by deep failures of leadership in Government," the committee said.
Sir Philip was accused of displaying a "determination to avoid unearthing the facts" during the inquiry into the "disaster" of the withdrawal as the Taliban seized power.
The fact that Sir Philip, the then-foreign secretary Dominic Raab and Prime Minister Boris Johnson were all on leave as Kabul fell last August marked a "fundamental lack of seriousness, grip or leadership at a time of national emergency", the MPs said.
Downing Street disputed aspects of the report and said the Prime Minister retains full confidence in Sir Philip as Foreign Commonwealth and Development Office (FCDO) permanent secretary, with the Prime Minister's official spokesman insisting it is not impossible to get fired from the Government.
Ministers were accused of having a "total absence of a plan" for Afghans who supported the British mission, despite knowing for 18 months that the evacuations may be necessary if the US withdrew its troops.
But the spokesman praised staff's efforts during the evacuation and said there was "significant pre-planning before that".