The Saudi delegation was led by Gen Khalid Humaidan, the head of the country’s General Intelligence Directorate. He was received by Syria’s Gen Ali Mamlouk, the architect of the push to crush the early years of the anti-Assad revolution and the key interlocutor with Russian forces, which took a significant stake in the conflict from September 2015.

Two years earlier, Riyadh had been central to a plan to oust Assad by arming anti-Assad forces near Damascus and encouraging defections to nearby Jordan, from where the Saudi leadership had expected Barack Obama to launch a push by US proxies to take the Syrian capital.