The head of Australia’s military says the Taliban’s rapid takeover of Afghanistan was made easier by President Ashraf Ghani fleeing to exile as well as poor decision-making by the army’s commanders on where to marshall forces.

Chief of the Defence Force Angus Campbell told the ANU’s Crawford Leadership Forum on Monday he had been surprised by the speed of the Afghanistan government’s collapse but this was always a possibility, and that the Australian government’s rescue mission had far exceeded expectations to airlift more than 4000 people out of Kabul.