Sir Keir Starmer has said the prime minister's was "incapable of international leadership."
Speaking in Parliament, Starmer said the government's actions had been "complacent and wrong."
He said many Afghans eligible for help under the Afghan relocation and assistance policy (Arap) scheme were not able to get out, even though they applied in good time.
Boris Johnson said 311 people eligible to come to Britain under the Afghan Relocations and Assistance Policy (ARAP) scheme were still in the country.
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Starmer says Johnson was 'incapable of international leadership' over Afghanistan