The first white British male to join Isis has been identified as Jack Letts, 20.

Letts, now known as Ibrahim or Abu Muhammed, reportedly travelled to Syria when he was 18, after converting to Islam.

He admitted to his parents he was with Isis in September 2014 and is understood to have married a woman from Fallujah, Iraq, shortly after arriving in Syria, The Times reports.

Letts reportedly comes from a secular, non-Islamic background. He studied at Cherwell school, Oxford. He is reported to have drank alcohol and occasionally smoked cannabis with his friends before converting to Islam.

His father is an organic farmer and archaeobotanist and his mother a books editor. Both are said to be extremely worried for his safety after he told them he was moving to Kuwait to study Arabic, when in fact he was travelling to Syria.

Some former school friends from Oxford named him 'Jihadi Jack' (Image taken from Facebook)

Jack Letts wearing a hood in a picture he posted to Facebook, possibly inside his home in Fallujah, Iraq (Facebook)

One former school friend told the paper: "At school he was very much the classroom clown and was liked by a lot of students.

"That's why this whole thing of him going to live in Syria and join Isis doesn't make any sense."

Some former school friends from Oxford reportedly named him "Jihadi Jack".

Now a frontline fighter for the militant group, he lives with his wife and son Muhammed in the Iraqi city of Fallujah, having earlier lived in Raqqa, Syria, MailOnline reports.

In pictures: The rise of Isis Show all 74 1 /74 In pictures: The rise of Isis In pictures: The rise of Isis Isis fighters Fighters of the Islamic State wave the group's flag from a damaged display of a government fighter jet following the battle for the Tabqa air base, in Raqqa, Syria AP In pictures: The rise of Isis Isis fighters Fighters from Islamic State group sit on their tank during a parade in Raqqa, Syria AP In pictures: The rise of Isis Isis fighters Fighters from the Islamic State group pray at the Tabqa air base after capturing it from the Syrian government in Raqqa, Syria AP In pictures: The rise of Isis Isis fighters Fighters from extremist Islamic State group parade in Raqqa, Syria AP In pictures: The rise of Isis Isis kidnapping A video uploaded to social networks shows men in underwear being marched barefoot along a desert road before being allegedly executed by Isis Getty Images In pictures: The rise of Isis Isis kidnapping Haruna Yukawa after his capture by Isis In pictures: The rise of Isis Isis kidnapping Khalinda Sharaf Ajour, a Yazidi, says two of her daughters were captured by Isis militants Washington Post In pictures: The rise of Isis Isis fighters Spokesperson for Isis Vice News via Youtube In pictures: The rise of Isis A pro-Isis leaflet A pro-Isis leaflet handed out on Oxford Street In London Ghaffar Hussain In pictures: The rise of Isis Isis fighters Isis Jihadists burn their passports In pictures: The rise of Isis Isis controls Syrian Aid A man collecting aid administered by Isis in Syria In pictures: The rise of Isis Isis controls Syrian Aid A woman collecting aid administered by Isis in Syria In pictures: The rise of Isis Isis controls Syrian Aid Local civilians queue for aid administered by Isis. 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He is thought to have taken an interest in the Middle East during the Arab Spring of 2011. He then started learning Arabic and attended the Madina Masjid, a mosque near his home in Oxford.

There is no evidence he was radicalised at the mosque, and some of his friends believe he was radicalised in private prayer meetings.