A British chef who fought with Kurdish forces against Islamic State (Isis) has been killed fighting the extremists near Raqqa, activists have said. Ryan Lock, 20, from Chichester, West Sussex, died on 21 December during an offensive to take the de facto Isis capital in northern Syria.

Lock, who is believed to have travelled to Syria in August last year for a six-month stint, died two months before he was due to come home.

It has been reported that Lock, who had no previous military experience, told family and friends that he was going on holiday to Turkey but then crossed over into war-torn Syria.

Lock joined the People's Defence Units (YPG) as one of many foreign volunteers on 4 September. He was given the nom de guerre "Berxwedan Givara" or "Resistance Guevara", after Argentinian revolutionary Che Guevara.

Lock's father, Jon, said in a statement according to the Guardian: "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."

In a letter, seen by the newspaper, the YPG said: "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."

Lock becomes the third Briton to be killed fighting the terrorists. Former Royal Marine Konstandinos Erik Scurfield, 25, from Barnsley, was the first when a missile hit his combat vehicle in March 2015 near the Syrian town of Tel Hamis.

On 21 July 2016, a second British citizen, 22-year-old dairy farmer Dean Carl Evans, was killed by a rocket-propelled grenade in the city of Manbij, northern Syria.

A Foreign Office spokesperson said: "The UK has advised for some time against all travel to Syria. As all UK consular services there are suspended, it is extremely difficult to confirm the status and whereabouts of British nationals in Syria. Anyone who does travel to these areas, for whatever reason, is putting themselves in considerable danger."