Mr Aslin, 28, is known by multiple names. When he fought alongside Syria’s Kurdish militia the People’s Protection Units (YPG) against Isis he was known as Rojhat, he then adopted the name Cossack Gundi when he joined as a volunteer fighter in the ranks of the Ukrainian Army. To some, he is known simply as Johnny.

Mr Aslin, a care worker at his hometown of Newark, Nottinghamshire, had no military experience when he left the UK for Syria in 2015. Before he boarded a plane to Sulaymaniyah in northern Iraq, he reportedly told border authorities he was going on a backpacking trip.