Helen Clark has described the chaos unfolding in Afghanistan as "one of the lowest points of Western foreign policy in decades".
The Taliban - a strict Islamist militant group that held the country before being ousted 20 years by invading Western forces following the September 11, 2001 attacks - appears to be back in control after a stunning military advance that took the world by surprise.
Clark, who as New Zealand Prime Minister committed Kiwi troops to the US-led Operation Enduring Freedom in 2001, said predictions the Taliban were months away from attacking the capital Kabul turned out to be completely wrong.
"It ranks alongside the collapsed invasion of Suez, it ranks alongside not reading the intelligence about the Tet Offensive in Vietnam and the disorderly withdrawal from there. This is catastrophic… it's a very sad day for Afghanistan… and the US is now left without leverage to influence that future."
The France-UK-Israel invasion of Suez came about after Egypt nationalised the canal, a key shipping lane previously owned by the French and British. It failed after Egypt sank every ship in it, rendering it useless for almost a year, and other powers threatened to destabilise the UK economy.
The Tet Offensive was a series of attacks by the Viet Cong in the late 1960s, the ferocity and scope of which surprised the Americans, emboldening the anti-war movement.
"The people who caused the Afghan people - particularly the girls and women - so much misery 20 years ago have just taken the country over again," said Clark, saying they should never have been trusted to uphold promises made during last year's peace talks. The Trump White House and the Taliban signed a deal early in 2020 for a withdrawal of US troops in 2021, giving the latter plenty of time to secretly prepare a military offensive.
"There seems to be quite a disconnect [between] what their negotiators sitting in comfort in Doha say to the international media and what commanders do on the ground," said Clark. "The Taliban are not very good at keeping their word - they wanted power, so they were probably prepared to say just about anything.
"So the lightning advance they made in August across the country seemed to take the US and British - who are the key players here - completely by surprise. But actually, it shouldn't have.
"If you signal that you're going to leave Afghanistan at the beginning of the fighting season - remember a lot of the country is under snow quite a lot of the year - but if you say at the beginning of the fighting season 'I'm out of here by the end of August', which is still summer, you have created a timeline for the Taliban to grab as much territory as they can, which is precisely what they did."
After being Prime Minister, Clark took on a leading role at the United Nations - serving as administrator of the UNDP for eight years. In that time, she said despite being driven out of power, the intelligence she received suggested the Taliban "never actually went away" - while they couldn't take cities thanks to the presence of foreign forces, they still held sway in the countryside.
"I think it's a huge underestimation of their capacity to take the country back that has brought us to this point."
Attempts to evacuate Westerners from Kabul as the Taliban arrived were derailed by scores of Afghans flooding the city's airport, also desperate to escape. Not long after Clark appeared on The AM Show on Tuesday, US President Joe Biden said there was "never a good time to withdraw US forces", blaming local Afghan forces and political leaders who "gave up".
"It is wrong to order American troops to step up when Afghanistan's own armed forces would not," he said. "I'm deeply saddened by the facts we now face, but I do not regret my decision to end America's warfighting in Afghanistan. I cannot and will not ask our troops to fight on endlessly in another country's civil war."
He said after 20 years it was obvious "no amount of military force would ever deliver a stable, united, secure, Afghanistan".
"I am now the fourth American President to preside over [the] war in Afghanistan. Two Democrats and two Republicans.
"I will not pass this responsibility on to a fifth President."
Clark said Western forces propping up a civilian government at least gave everyday Afghans some hope - which now appears to be gone.
"Not everything's gone well and not every child has been in school, but if you compare what was happening before the Taliban was ousted with now, there was very, very significant progress in one of the poorest countries on Earth.
"That is what is now completely at risk. Unless the Taliban is the very exceptional leopard that changes its spots, we expect to see significant restrictions on the freedom of women who achieve their full potential."