Ryan Lock, 20, who had no previous military experience, travelled to Syria last August to fight alongside Kurdish forces.

A British man has been killed fighting against Islamic State in northern Syria, his family and Kurdish activists have said.

Ryan Lock, 20, from Chichester, West Sussex, died on 21 December during an offensive by anti-Islamic State forces to recapture the city of Raqqa, the extremist group’s de facto capital.

Lock’s father, Jon, said in a statement: “Ryan was a very caring and loving boy who would do any thing to help anyone. He had a heart of gold. We ask for privacy to allow our family to grieve.”

Lock, who had no previous military experience and had worked as a chef before travelling to Syria, was one of many foreign volunteers who have joined the People’s Defence Units (YPG), the Kurdish military force fighting in northern Syria.

In a letter, the YPG offered their condolences to his family, saying: “Ryan joined actively in our offensive against the terror threat that Isis caused upon Rojava, Kurdistan. Here, on the dark hours of 21 December 2016, we lost our brave companion Ryan and four other fighters in Jaeber village.

“Ryan was not only a fighter providing additional force to our struggle. In fact, with his experience and knowledge he has been an example for younger fighters.

While he has reached a vast amount of achievement up in our frontlines, Ryan has served the purpose of a very important bridge between us, the Kurds of Rojava. He crossed continents for the destiny of our people and humanity.”

It is understood that Lock travelled to Syria last August after telling family and friends that he was going to Turkey on holiday.