The government says the situation in Afghanistan means the British Embassy in Kabul cannot finalise plans.
Afghan students offered scholarships by the UK government to study here from next month have been told they will not now be able to take up their places.
Chevening Scholarships enable promising students around the world to pursue a masters degree in the UK.
But the Foreign Office said the situation in Afghanistan meant the British Embassy there would not finish preparations in time for this year.
The decision has been criticised by two former Conservative cabinet ministers.
Chevening Scholarships, which are funded by the Foreign Office, are prestigious and highly competitive.
But Afghan students who have been awarded places for this coming academic year have been told the embassy in Kabul, Afghanistan’s capital city, will not be able to complete the paperwork.
It comes as the Taliban continues to seize territory in the country following the withdrawal of US and other foreign troops after 20 years of military operations.
The former Conservative cabinet minister David Lidington said on Twitter that the decision to withdraw the scholarships seemed both “morally wrong and against UK interests”.
“Surely those accepted onto #Chevening will be at particular risk from Taliban & among “brightest & best” whom our government rightly wants to attract to UK,” he said.
Mr Lidington added that he hoped Prime Minister Boris Johnson and Foreign Secretary Dominic Raab would review the situation “urgently”.
Former international development secretary Rory Stewart said it was “deeply disappointing” that visas could not be sorted out.
A Foreign Office spokesperson said all of this year’s scholars would be able to start their programme next year.
The Taliban has seized what had been government-controlled territory with speed following the withdrawal of foreign troops.
The militant group is now in control of much of the country and is edging closer to the capital Kabul.
This week the UK government said it would send about 600 troops to the country to assist British nationals to leave.
More than a quarter of a million people have been displaced by the violence, and many have fled Kabul in the hope of finding safety.
Gen Sir Richard Barrons, who was head of UK Joint Forces Command, previously warned that the withdrawal of troops from Afghanistan was a strategic mistake that risked a resurgence of terrorism.