As the Taliban closed in on Kabul, and Western troops and desperate Afghans scrambled to leave, Britain found itself frozen out of decision making and incapable of influencing events. It was a stark illustration of the UK’s status, made worse by catastrophic misjudgements at the top of government. In this two-part Slow Newscast, Matthew d’Ancona investigates what was happening in Westminster and Whitehall as the West abandoned the country it had liberated 20 years before.

In Kabul, the Taliban’s takeover was assured. In London, an ignominious retreat, and the betrayal of former comrades in the Afghan army, was more than a group of ex-soldiers, now MPs, could stomach...