Thousands of children are living in appalling conditions on the Greek island. At the Moria camp, one Syrian teenager tells of trying to join his family in the UK

Outside the Moria refugee camp in Lesbos, a shanty town made of tarpaulin strung between olive trees is getting bigger every week. There are now 18,000 people living in this second camp, designed for just over 2,000.

Ahmed (not his real name), 17, and his friend Musa wind their way up muddy tracks towards their tent, swerving to avoid groups of children running in flip-flops through the dirt.

The boys have made their home under plastic and they want to show us how they are living, huddling in a group of three to keep warm. Ahmed has been here since October, when he arrived from Syria expecting to move quickly onwards.

Although he knew nothing of the laws on family reunion when he set out from his village near Aleppo, Ahmed knows now that his family in the north of England – a brother and cousin who are desperate to give him a home – are his only hope of escaping Moria. But he is worried. “It is so slow, and I know if we do not get into the system quickly it might not happen.”

Last week British MPs voted to reject proposals that would have kept protections for child refugees in the redrafted EU withdrawal agreement bill. MPs voted 348 to 252 against the amendment, which would have guaranteed the right of unaccompanied child refugees to be reunited with family members living in the UK.

Safe Passage, the charity helping Ahmed, works across Europe to help children, some under 10 years old, apply to join family members in the UK. It says that 95% of its cases would be impossible without the EU law on family reunion, because British law only allows children to join their parents. Ahmed’s case, a boy wanting to join his brother, is far more common.

The charity has been contacted in recent months by many worried families who are afraid of losing the small chance of saving a young cousin or sibling from taking the dangerous journey across Europe alone. Charities know that the risks of this journey include widespread exploitation and abuse.

When Ahmed left his village last year he had no plan to reach his brother. He thought he would just keep walking and crossing borders until, with difficulty, he might reach safety in northern Europe.

“The smugglers lied,” he says. “I thought I would spend one night maybe in Lesbos and just keep moving forward through the forests like I did all the way from Syria. I had no idea I would be stuck like this.”

Ten minutes’ drive from the holiday resort of Mytilene, the scene around him is tough. There is no electricity and very little water. Among piles of rubbish, thousands of people are busy surviving, pulling branches from the olive grove for fires to cook on, rolling flour into flatbreads, stringing tarpaulin over pallets to make new shelters. Women breastfeed on the muddy ground. And there are hundreds of children. According to the UNHCR, 42% of the 20,000 migrants in and around Moria are under 18, and nearly half of those are under 12.

Facebook Twitter Pinterest Syrian refugee Ahmed: ‘I had no idea I would be stuck like this.’ Photograph: Giorgos Moutafis/the Observer

Ahmed, whose curls are pushed under a woolly hat, is bundled inside an oversized coat, scarf and tracksuit trousers. His family began to plan his escape when he turned 15. “For young men, as you get to this age it is very dangerous. Someone will make you come and fight and kill your friends, your brothers.

“Many people had already left, and after a year of talking, my parents decided I should leave, they are too old but I can go. It was so difficult, nobody wants to leave home. When the situation became so bad, I had to go. Our house had been destroyed by bombs.”

His journey was brutal: one of his friends was shot dead as they crossed the Turkish border. When he first arrived at Moria, nightmares of the sea journey woke him screaming in the night, disturbing people around him.

“Inside the main camp there are many adults and a lot of fighting. It is better out here. My parents are very worried about me, they don’t want their son in this situation. They sometimes regret letting me leave and sometimes they say it was the only choice.”

Ahmed wants to know why, if there is a law that lets him join his brother, it is such a confusing and long process.

His case is a drop in the ocean for Greece, a country with 4,000 unaccompanied minors to look after. On a visit to the Greek islands last month, the UN high commissioner for refugees, Filippo Grandi, called for Europe to do more. “Europe has to get its act together,” he said after visiting Lesbos. “ There is a children on-the-move emergency in this country that needs to be tackled.”

Almost every day a boat arrives in Lesbos from Turkey, bringing more desperate people. Huge numbers of them are women and children. On Thursday night a boat came with 57 people, 33 of them children.

For now, Ahmed’s brother is sending him money to try to help him survive while Safe Passage pushes his case to join his family in northern England. What does he know about the market town where his family are waiting for him? He laughs. “I don’t know anything, but I know it is better than Lesbos.”