An 18-year-old British boy has been arrested for allegedly having sex with a 17-year-old girl in Dubai.

Detained in Dubai, a group of UAE legal experts, said the teenager was on holiday with his parents when he met the girl — who is now 18 — at the same hotel.

The teenagers who are both from London were said to have made plans to continue their romance when they returned to the UK.

The group, which campaigns to help people it says have suffered injustice in the UAE, said the young man was charged because the girl’s mother found their chats and pictures back in the UK.

It was gathered that the woman subsequently contacted police in Dubai and he was arrested.

The boy however claimed he was unaware that the girl was younger than him when they met. The teenager also disclosed that he was in police custody for three days and was unable to contact his parents.

“We had a wonderful time together. We really liked each other but she was secretive with her family because they were strict,” he told Detained in Dubai.

“My parents knew about our relationship but she couldn’t tell hers. She had to meet me without telling them it was to see a boy.

“When she left, I couldn’t wait to see her again when I got home. Then suddenly, police knocked on our hotel door. They said they were taking me in for questioning but wouldn’t tell me why. I was frightened and my parents were terrified.”

The teenager, it is understood, could face up to two decades in prison owing to Dubai’s strict laws regarding sex outside marriage.

Radha Stirling, chief executive of the campaign group, said Dubai recently legalised out-of-wedlock sex for tourists but “still hosts a strict Islamic legal system”.

“Sex outside marriage is legal for tourists but only if both parties are over 18. The girl was just a few months younger than Marcus and he didn’t know that at the time,” Stirling said.

“Since his arrest, she has turned 18. This is not something Dubai should be prosecuting.

“Parents will be scared to take their older teenagers on vacation with them where they could end up losing their lives over behaviour that’s completely legal in their own countries.”

The teenager and his family have called on foreign secretary David Lammy, their local MP, to intervene in the case.

The teenager is no longer being held in a police cell but is unable to leave the country, with his family facing bills of £2,000 for Airbnb accommodation until his case is resolved.