THE former director of the CIA has warned MPs there's a "human catastrophe" beginning due to the west's withdrawal from Afghanistan.

Retired US General David Petraeus, a former Nato commander who led the International Security Assistance Force in Afghanistan, says that country could now slip into a "meltdown" that makes it a "geopolitical Chernobyl" on a par with the Syria crisis.

The outpouring of refugees from Syria helped create the so-called European refugee crisis that itself became a central part of the Brexit debate.

Appearing before the cross-party Foreign Affairs Committee, which is holding an inquiry into UK Government policy on Afghanistan, Petraeus said he'd forecast the collapse of the country's security forces as a direct result of US and UK military withdrawal.

He said: "I feared that what did happen would actually happen.

"I publicly said that I feared a psychological collapse of the Afghan security forces and, of course, that’s what did transpire.

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"It’s very hard to say this result is anything but heartbreaking, tragic and, in many respects, disastrous."

And he went on: "The human catastrophe that is looming in Afghanistan is going to be one which will require the world to take action."

Petraeus' appearance came after leaked messages to Foreign Secretary Dominic Raab from UK ambassador Laurie Bristow revealed he was warned the Taliban were poised to move on Kabul as a result of the withdrawal of western forces.

Raab, who was on holiday as the crisis unfolded, had said noone had seen it coming, but the cables seen by the Times newspaper state that "the Taliban will wait until it believes international military withdrawal is irreversible before escalating its campaign".

Petraeus said there had been "a serious miscalculation" over the withdrawal, highlighting the "moral responsibility" to the Afghan workers and left behind and stating: "What were we thinking to have all the military out?"

He said the Taliban "has no money" as the US cuts off the cash it used to provide and "the prospect for the Afghan people is one that's very, very bleak indeed" as the country copes with drought on top of food insecurity and economic struggles.

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Petraeus said: "We don't want to see another geopolitical Chernobyl like Syria, the meltdown of a country that spews millions of refugees all the way into Europe causing the biggest domestic populism challenges that European democracies have faced at the very least since the end of the Cold War."

He cautioned that Pakistan "is going to be the country under the most pressure" as it is the "logical recipient of the refugee flow": "They can try to close the Khyber Pass and the other borders and all the rest of that, but there’s many ways to get across if you’re sufficiently desperate.

"Tragically, Afghans are already sufficiently desperate and they are going to get even more so as food stuffs and humanitarian assistance and so forth come up short."

The session came 50 days after UK and US troops left Afghanistan.

Local authorities in Scotland are amongst those now working with the Home Office to house and support the refugees brought here as part of the emergency evacuation and relocation programme for former interpreters and other civilian staff.

The UK Government has committed to welcome around 5000 people within 12 months as part of a broader resettlement scheme which will take in up to 20,000. UN agencies will help to identify "those we should help", the Tory administration has said.