The loss of Aleppo to Islamist rebels represents a stunning defeat for the Syrian regime, highlighting its dependence on enfeebled allies.

The Syrian army said on Saturday dozens of its soldiers had been killed in a major attack led by Islamist Hayat Tahrir al-Sham rebels who swept into the city of Aleppo, forcing the army to redeploy in the biggest challenge to President Bashar al-Assad in years.

Time and time again the Assad dynasty has survived internal and external challenges and lived to fight another day. But nothing lasts forever.