Last October, Ishmael was one of many despairing migrants living in huts in Calais, risking his life regularly in an attempt to stow away in trucks to get to Britain, depressed to have fled violence in Syria only to find himself stuck in the squalor of the camp.

Now 18, Ishmael is settled with a foster family in north London and his English — almost non-existent when he left Syria alone aged 15 — is rapidly becoming fluent. He will soon begin a foundation course in politics at Birkbeck, University of London, the recipient of one of the college’s Compass scholarships, which provide financial support for asylum seekers.

It is an incredibly cheering experience to interview him at his new home and hear his optimism and excitement about his future. After reporting from the Calais camp, witnessing the misery of hundreds of teenage refugees who had no idea what was to become of their lives, it is lovely to find someone for whom things have turned out so well.

It feels remarkable even to be able to have a conversation with Ishmael in such a normal, stable environment, over late breakfast around the kitchen table, the family dog running around – far from the hunger and cold of Calais.

Without the support of Safe Passage, one of three refugee charities supported by the Guardian’s readers as part of our 2016 charity appeal, it is unlikely things would have unfolded so positively for Ishmael. This is partly why he wants to talk about his experiences.

He spent almost 17 months travelling to Britain, an extraordinary undertaking for a 15-year-old. When it became obvious that his life would be at risk if he stayed in Syria, his mother sold her jewellery to fund his journey. Just two of the 30 children in his school class remain in Syria; the rest are scattered around the world, most in refugee camps in Turkey.

“It is not that I’ve come here in a search of a good life,” Ishmael explains. “I’ve not come for economic reasons. I had a fantastic life but I would have been killed if I stayed there.”

His parents, while worried for him, agreed it was the right decision. He tried not to upset them unnecessarily, shielding them from the difficulties of day-to-day life on the road, his fears and mounting unhappiness. Shortly after he arrived in Calais, Ishmael’s mobile phone and computer were stolen, so he was unable to contact them for two months. He managed to get someone to send them a text saying: “I’ve lost my phone; don’t worry about me.”

In the 14 months he spent in France, Ishmael estimates that he tried to stow away in lorries more than 100 times. Once he even made it on to a boat before being discovered by British ferry workers and sent back to Calais.

Last October, as the camp was being demolished around him, the charity Safe Passage told Ishmael they had secured papers for him to be transferred legally to London under the Dubs scheme, created by a legal provision introduced by the Labour peer Alf Dubs to allow for vulnerable unaccompanied refugee children to be brought to Britain. He thought they were lying. “It was such a shock. I thought I was dreaming. Suddenly I forgot all the pain,” he recalls.

He has landed on his feet with a friendly foster family, welcomed by their 14-year-old daughter and 23-year-old son. His perceptions of Britain were vague, formed mostly by watching Britain’s Got Talent in Syria before his family were forced to flee from their home in Aleppo to the countryside. Despite knowing little about England, he had an idea that it was a country that respected democratic values and was welcoming towards refugees. He tried to teach himself English as a child, watching Lord of the Rings and the Hobbit in English with subtitles. He is an Arsenal supporter; by extra good fortune his foster family have an Arsenal season ticket.

Last December, Guardian readers raised £1.75m, a sum split between three charities supporting refugees: Safe Passage, Help Refugees and the Children’s Society. The money that went to Safe Passage has helped the organisation continue its work finding legal ways to bring refugee children to Britain. Only 200 arrived under the Dubs scheme – well short of the 3,000 campaigners had hoped for and 280 short of the government’s latest commitment. However, Safe Passage’s work has meant that about another 1,000 refugee children have been legally reunited with family in the UK using different legislation.

While Ishmael waits to start college, he has been doing work experience with Dubs, whose campaign forced the government to start taking some child refugees from Europe. He has spoken in parliament about his journey, and wants to campaign for the UK to be more open to taking refugees.

Having seen the risks of attempting to travel illegally, Ishmael makes a strong case for a legal route. “It was always dangerous. Every attempt you make includes a risk, from the police, from the road, from the driver who may hit you if he sees you,” he says. “That I wasted more than a year trying to get here illegally is very hard to remember.”

He worries about his 14-year-old nephew, currently attempting a similar journey, traveling alone through Europe in an attempt to find safety.

The arrest of a Syrian refugee over the Parson’s Green tube bombing last month has worsened attitudes towards refugees in Britain. Ishmael, surrounded by supportive new friends, says he has not experienced hostility, but feels a responsibility to fight prejudice: “I want to make people feel positive about refugees,” he says.

His only frustration with his new country is focused on the Home Office and the delayed response to his application to stay, which almost jeopardised his course at Birkbeck.

The teenager would liketo return home eventually, but only if President Bashar al-Assad and Isis are defeated. He doesn’t know if his home in Aleppo is still standing. In the meantime he wants to study and then work in the UK; he plans to go to King’s College London next year.

Laura Griffiths, who manages casework for Safe Passage, describes the enormous relief she felt that Ishmael managed to get to the UK legally. “I first met Ishmael in Calais in October 2016. His was a particularly striking case as he had been travelling for so long, from such a young age,” she says. “Life in the Calais camp was always chaotic, but at that time it was particularly unstable; reports of the imminent demolition meant children were scared, and Safe Passage were trying to work on as many cases as possible to transfer children out of the camp.”

She has been impressed at Ishmael’s readiness to campaign for others in a similar situation. “Since he has been here, he has been involved in Safe Passage’s advocacy programme, meeting MPs and raising awareness about the importance of establishing safe routes for child refugees.”

Jonathan Clark, bishop of Croydon and chairman of Safe Passage, notes that the charity’s work has been able to continue because of Guardian readers’ support. “We are enormously grateful to the readers of the Guardian, who have helped us transform the lives of hundreds of young people,” he says.

“Thanks to your generosity, we were able to respond to the growing number of unaccompanied children arriving in Italy earlier this year; we have started to establish inter-Europe family reunion, helping unaccompanied children to reunite with their families across Europe; and we have begun to extend our work beyond Europe.”

Donations allowed for an expansion of the team who support new arrivals in the UK, he says. “Thanks to your readers, many children are now sleeping safely and securely in warm beds, and many more will not have to risk their lives trying to reach sanctuary.”