The former UN special envoy to Syria claimed that he quit his post because he realised President Bashar al-Assad had won the war and did not want to have to shake his hand.

Staffan de Mistura, who was in the position from 2014-2018, said he could not live with himself if he stayed on to oversee Assad’s victory.

His tenure marked the deadliest period of the Syrian conflict, in which tens of thousands were killed, including in chemical weapons attacks, and a Russian intervention helped swing the war in the regime’s favour.

“Why did I leave last year? Well, officially, for personal reasons,” the 72-year-old Italian-Swedish diplomat said, speaking at the Aga Khan Centre in London on Tuesday in one of his first interviews since standing down.

“Unofficially, because I felt the war territorially was leading to an end and having really fought against what happened in Aleppo, in Idlib, in Daraya, I could not be the one that is shaking Assad’s hand and saying ma'lesh [meaning don’t worry in Arabic],” he said, referring to rebel-held cities which endured intense bombing before falling to government forces.