Commentators spoke of a last desperate gamble to bring an end to conflict that has gone on so long that there are western soldiers soon to be deployed to the country who were in nappies when it started in 2001. Last week Ashraf Ghani, Afghanistan’s embattled president, announced a bold plan to draw the Taliban into a binding peace process. It is a stalemate which has left thousands of civilians dead. The war, part of a Saudi policy of adopting a more aggressive external posture, is not going well. One topic he will be discussing with British policymakers is the war raging since 2015 in its neighbour Yemen, where Saudi forces lead an alliance of regional powers against Houthi rebels. This week Mohammad bin Salman, the young Saudi Arabian crown prince, will be in London.