Raihan was playing football with his friends the day the Myanmar army came to his village.

Now aged 10, he is one of more than 6,000 orphaned or unaccompanied Rohingya children living as refugees in Cox’s Bazar, Bangladesh.

Describing what happened, exactly one year ago today, he says the first sign that something was wrong came from the smoke and flames rising from his neighbours’ houses.

“My parents and sisters grabbed me and tried to run, but the military got hold of my parents and killed them, there and then,” he says. “My sisters ran towards my parents and the military killed them too.

“I didn’t know what to do so I ran away – I was so scared. It felt like all the blood drained from my body and I didn’t know if I could keep running. I didn’t know where I was going and all I could think of was my parents and sisters lying on the ground.”

Raihan reached the next village and joined a group of fellow Rohingya Muslims, also fleeing for their lives. Together they walked for three days to get to Bangladesh. “No one knew me, and I didn’t know what to do. I just followed all the crowds,” he says. “I didn’t eat anything during those three days.”

Raihan lost his whole family in the violent military crackdown on 25 August last year. He now lives with his aunt as a refugee in Bangladesh (Unicef/Alexandra Murdoch)

Orphans represent some of the most vulnerable members of the more than 700,000-strong Rohingya community that fled northern Myanmar as a result of a military crackdown on 25 August last year. The UN has referred to what happened as a “textbook example” of ethnic cleansing.

Raihan says he misses his parents – even them telling him off for being naughty – but he is at least lucky in the sense that he found his aunt, also living in the Cox’s Bazar camps. “I don’t know where I would be now,” without her, he says. He has even been able to start playing football again.

A new study, released this week to mark the one-year anniversary since the military crackdown, suggests that some 70 per cent of all unaccompanied Rohingya children were separated from their parents or guardians through violent attacks.

Save The Children said the survey, involving 139 unaccompanied and separated Rohingya children, was the largest of its type conducted so far in Cox’s Bazar. It dispels the previously held belief that many children had lost contact with their families in the chaos of fleeing over the border to Bangladesh.

Joining up separated children with extended families or foster parents in the camps has proved difficult. According to Unicef, up to 10 per cent of the entire camp population consists of children living without a guardian.

Arefa* was 16 when the army came to her village. She had gone to collect water, and when she came back saw from a distance that the armed forces were outside her home.

She says she hid in the bushes with her neighbours and watched as the army starting shooting, first the old people and children. When the other adults started shouting “stop, stop”, they shot them too.

Among those killed in front of her were her father, mother and seven brothers and sisters.

She fled with neighbours to Bangladesh and now lives alone, only receiving occasional counselling and support from girls-only centres in the camp.

Arefa receives weekly visits from Keya, a 23-year-old Bangladeshi anthropology student who is volunteering with Save The Children as a case worker in Cox’s Bazar.

She explains that Arefa’s traumatic experience means she cannot face living with foster parents, and at 17 years old it is her right to choose to live alone. “She has already lost everyone, there is no one left for her, she does not want to live with another family,” Keya says.

​Tasmin* is another of Keya’s cases. She is 15 years old and severely disabled, a birth defect leaving her without the use of her legs.

She was totally dependent on her father, a baker, in Myanmar – he was “the only person looking out for her on Earth”, Keya says.

Tasmin hid in the kitchen when the army came last year, and saw the soldiers lining up all male villagers aged between 20 and 50, gunning them down. Her father was among them.

According to Keya, Tasmin was then forced to crawl for 12 days to reach the Bangladesh border, dragging herself along by her arms.

“When she arrived here at the camp she was covered in blood, there were cuts on her hands that had become infected,” Keya says.

Tasmin now has a foster family to look out for her, and aid workers have provided her with a wheelchair, as well as regular sessions with a psychological counsellor.

Drawings by Rohingya children Show all 18 1 /18 Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Save the Children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children Drawings by Rohingya children

Save The Children say that orphaned refugees are at far higher risk of abduction, sexual and labour exploitation, as well as more likely to suffer long-term psychological symptoms of distress.

“Twelve months ago, our teams saw children arriving in Bangladesh on their own, so distressed, hungry and exhausted they couldn’t speak,” says Save the Children’s country director in Bangladesh, Mark Pierce.

“We set up spaces for these children to receive 24-hour support while we searched for their families. One year later, it’s clear that for many, this reunification will never take place.

“These children are some of the most vulnerable on the planet, and they have had to carve out an entirely new existence in the camps, without their mother or father, in an environment where they are far more vulnerable to risks like trafficking, early marriage and other forms of exploitation.”

Unicef is using this week’s anniversary to call for proper funding for education for the hundreds of thousands of displaced Rohingya children, as well as progress on achieving them statehood. Currently, neither Myanmar nor Bangladesh recognise the rights of the Rohingya people to citizenship.

And Save The Children said countries like the UK could do more to hold Myanmar to account for the brutal actions that led to the crisis. The authorities in Myanmar have consistently denied any atrocities, saying they were simply responding to the violent activities of a Rohingya militant group.

Save the Children’s advocacy director George Graham said: “A credible, impartial, and independent investigation into these crimes and all violations of children’s rights committed in northern Rakhine State is a key first step towards ensuring accountability.

“The foreign secretary Jeremy Hunt has an opportunity to show leadership by pushing to refer the perpetrators of these systematic, ruthless and deliberate attacks to the International Criminal Court.”