A VULNERABLE teenager being held in prison in Japan on drug smuggling charges has spoken about his ordeal for the first time.

Autistic Sean Stephenson, 19, from Charlton, London, was arrested at Tokyo Airport in June after his suitcase was found to contain more than 10kg of methamphetamine.

His family are adamant drug gangs have taken advantage of the teen, having allegedly groomed him into travelling first to Portugal and Canada before being caught in the Japanese capital.

Sean sent a letter back home to his family - the contents of which have been shared with The Sun - in which he admits "I'm scared" and reveals he's been moved to a new facility which is "so strict".

Written in his cell, the young man penned the note on his birthday last month, telling his loved ones: "Dear family and friends, I hope you're all doing good. I'm okay.

"I can't believe I'm 19 today. I miss you all so much, please be assured that I'm coming back and I know we will meet again some sunny day.

"To be completely honest with you, this new place they have sent me is so strict and they make you buy the majority of your necessities.

"To be honest, I'm scared. I love you to the moon and back. Lots of love, Seany."

Arrest at Tokyo Airport

Sean was arrested on June 21 after he was found with a locked suitcase containing the illegal substances.

Though legally an adult, Sean has a much younger mental age and is eager to make new friends - something his family say was taken advantage of.

He has multiple physical and mental health challenges and was diagnosed with autism spectrum disorder (ASD) aged five.

Everything his family know about his movements has come through information provided by his solicitor in Japan, but they're unable to speak to him directly.

It was through Sean's legal rep that his family were able to contact him and exchange multiple letters.

Sean's sister, Ami Lee, who has three children of her own, told The Sun: "Some of the letters he's written, he thinks he's going to come home and he hasn't got a family.

"That we're going to disown him. All these thoughts running through his head.

"In some letters he's saying he's okay, then he's saying 'I'm not doing so great today but hope to speak to you soon'.

"He says 'please don't give up on me, my worry is that you'll leave and disown me'.

"Then it's another week, three weeks, until we get another letter."

Ami has been fighting to find out what's happening to her younger brother nearly 6,000 miles away and last saw him on June 14 at her daughter's birthday.

She added: "I'm still up all the time, constantly, you know, worrying about my brother.

"My phone's constantly ringing at 12 o'clock at night, it's the solicitor and I'm worrying if my brother's okay, I'm not sleeping."

She has been desperately trying to raise enough funds for Sean's legal fees and he said in a previous letter that he'd "really like to keep this solicitor".

"The lawyers are asking for £1,000 a month, we're trying to find a venue for a fundraiser, we're doing scratch cards but a lot of people don't want to be associated because of the drugs," she said.

But now, Ami has since revealed that they can no longer afford Sean's legal fees as they weren't able to raise enough, leaving him "very upset".

"We're just in limbo at the moment, trying to see who he's new solicitor will be," she said.

"The only contact we've got now is with the embassy. This means all contact is kind of at a halt, it's very, very minimal."

'My son was groomed and trafficked'

Having never travelled abroad before, let alone by himself, Sean's disappearance stunned the entire family.

Out of the blue, he became adamant he wanted to go on a solo foreign trip but then vanished overseas on Father's Day morning and the family later received news that he had been detailed in Japan.

Sean's mum, Star Lee, 57, has also spoken to The Sun and described the ordeal as "torture".

"I'm in limbo, my son is in Japan, he's got ASD, he was groomed and trafficked. I just need to tell my boy it's going to be okay," she said.

"I haven't seen him since June, I haven't spoken to him. Every day is hard, and it's getting harder. Justice needs to be done."

His family describe him as extremely vulnerable with a mental age of "12 to 13 years old".

They describe him as "so helpful and kind" - he was Star's carer and, before his grandmother passed away in February, he "did not leave her bedside" and would get her medication everyday from the chemist, she explained.

Star added: "He's never in trouble, he's not rude to everyone, everyone around here loves Sean.

"The support in the community has been unbelievable, everyone's come together because they love him.

"Even one woman said 'he used to carry my bag when he used to see me struggling', he never brought the police to my door, nothing."

Sean's sister believes he was picked up outside a Nisa shop one morning by a man who had befriended him and escorted him to Heathrow Airport.

His phone and bank cards were taken and he was given a Nokia so he couldn't contact his family and arrangements were made for Sean to meet another man in Toronto.

According to the solicitor at the time, Sean received threats to "break his legs and hurt his family" if he didn't go to Canada.

From Toronto he was handed the suitcase of drugs to take to Tokyo where he was told it was money to be dropped to a "friend", she claims.

"They sold him a dream, they sold my boy a dream. He's a good boy," Star said.

"God knows what they've done to my boy. Took his phone off him, took all communication from him as soon as he got to the airport and then bullied him from there. He must be frightened and scared.

"It's not fair they've taken my boy's life away from him."

Asked what she would say to Sean if she could speak to him on the phone, she said: "Oh, that everybody loves him. I love him.

"That it's not his fault, not his fault at all. I don't want him to feel like that.

"I love and miss him and just want my boy home. I feel like I've lost him, I'm grieving for my boy, and it's making me ill."

'I don't know anything'

Star added that she thinks there's "not enough support for my son" in Japan and said "I haven't even got a photo to know that he's okay".

Star also highlighted the lack of support she's received since her son disappeared, saying she felt "very let down" by the system.

"I don't know anything, I don't know know when he's in court. I just feel like I'm going mad. It's horrible and there's just no one helping me.

"The police haven't even rung me, my son's going to trial, they told us he's looking at 10 to 14 years.

"His vulnerable, he's tried to take his life before".

"I just feel let down by everyone really, I wrote to the MP. He never got back to me. The embassy's hard to get on with as they have their own laws. They might have their own laws, but surely I'm entitled to hear my son from a phone call?

"I feel like the system's let my son down, we really do as there's other kids out there you know, like mine's out there. Other people in this area are vulnerable with disabilities."