One child, Abu al-Bara’a al-Tunisi, then says “To the atheist Kurds, what is between me and you are days during which the hair of young children turns grey. The war with you has yet to begin. Neither America, France, Britain, nor Germany will benefit you,” according to Site Intelligence Group, which monitors jihadi propaganda.

Elsewhere, the video shows old men killing Syrian soldiers and other fighters beheading four men from rival rebel factions.

Meanwhile, a radicalised student was on Friday sentenced to seven years in prison for helping a friend go to Syria to fight while studying for his A-levels.

Abdullahi Ahmed Jama Farah, now 20, created a “hub of communication” for his “Mandem” group of like-minded extremists from his mother’s home in Manchester in 2013.