Exclusive: 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.

In a message on Facebook on 31 August, he wrote: “I’m on my way to Rojava. I lied about going to Turkey. I’m sorry I didn’t tell anyone. I love all of you and I will be back in six months.”

He joined up with the YPG on 4 September where he was given the nom de guerre Berxwedan Givara, meaning “resistance Guevara”, after the Communist revolutionary Che Guevara.

On 24 November he witnessed the deaths of most of his unit when it was bombed, allegedly by Turkish jets, in Arima, a village 13 miles north-east of the Isis-held city of Bab.

Twelve YPG fighters were killed in the airstrike, including an American, Michael Israel, and a German national, Anton Leschek.

Afterwards, Lock posted a picture of himself with facial injuries, along with the words: “We were taking a small village when we got hit by Turkish jets in the night. Two of my friends, Anton and Michael, were killed among many others. I’m staying to finish out my six months. Fuck [Turkey’s president Recep Tayyip] Erdoğan and fuck Turkey.”

The United States has supported the Kurdish-led forces in their fight against Islamic State, infuriating Ankara which sees the YPG as an extension of the Kurdish PKK militants who have waged a three-decade insurgency in south-east Turkey.

Turkey fears the YPG will try to connect three de facto autonomous Kurdish cantons that have emerged during the five-year war to create a Kurdish-run enclave in northern Syria, stoking the Kurds’ desire for autonomy on its own soil.

Little is yet known about Lock’s motivations for joining the fight against Isis in Syria,

Ozkan Ozdil, a 30-year-old north Londoner who arrived in Syria last September, said Lock was “always upbeat with a smile on his face”.

He said: “I met Ryan at the academy and he graduated 10 or so days later. He was a nice guy, always telling jokes, but he didn’t make his motives obvious to me.

“He was liked and seemed very motivated to be involved in fighting. He was very supportive of the Kurdish cause. He said he came to make a difference where many wouldn’t dare step up.”

Mark Campbell, a Kurdish rights campaigner who was among a Kurdish delegation that visited Lock’s family on Sunday, said: “The family are understandably in a state of absolute grief at the news and will not be making any statements to the media. The thoughts and prayers of the Kurdish community are with the Lock family today and are ready to help the family in any way they can.”

For the past two months Raqqa has been the focus of heavy fighting as the mostly Kurdish Syrian Democratic Forces (SDF) – which includes the YPG – try to drive Isis from the city.

Raqqa has been under Isis control since early 2014 and is home to nearly 200,000 mostly Sunni Arabs and an estimated 5,000 IS fighters, including some of the group’s leaders.

The SDF operation coincides with a campaign to recapture Mosul across the border in Iraq. The two cities are Isis’s last major strongholds after a series of heavy military losses in recent months, and are seen collectively as the key to defeating the group militarily.

Lock is the third British man to be killed fighting against Isis since the first foreign volunteers arrived in Iraq and Syria in the autumn of 2014.

Konstandinos Erik Scurfield, a 25-year-old former Royal Marine from Barnsley, became the first when a missile hit his combat vehicle on 2 March 2015 during heavy fighting near the north-east Syrian town of Tel Hamis.

On 21 July 2016, Dean Evans, 22, a dairy farmer from Warminster, was killed by a rocket-propelled grenade as he attempted to rescue a fallen comrade during a street battle in the city of Manbij, northern Syria.

A Foreign Office spokesperson said on Monday: “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.”