Memorial services have been taking place today to mark 20 years since UK operations began in Afghanistan.
Wreaths were laid at the Bastion Memorial in the National Arboretum in Staffordshire and in central London to the 457 service personnel who lost their lives.
We spoke to General Stanley McChrystal – who commanded US and British forces when he led the International Security Assistance Force in Afghanistan. He has published a new book on the best ways to assess and mitigate risk.
We asked him first what he thought of President Biden’s decision to pull out of Afghanistan?