Posing with an assault rifle after joining rebels fighting the Syrian regime, this is the British son of a suspected Al Qaeda mastermind.

Abdel-Majed Abdel Bary, 23, is the latest in a growing stream of young men to join militant groups in the war-torn Middle Eastern country.

He walked out of his family’s £1million home several months ago telling them he was “leaving everything for the sake of Allah”.

Friends said Bary – an aspiring rapper on the ‘grime’ music scene – grew increasingly radical and violent after mixing with thugs linked to hate preacher Anjem Choudary.

He has posted a series of photographs online, including shots of him masked and posing with guns under the title ‘soldier of Allah’.

In other messages he called on Allah to ‘grant us martyrdom’, and praised Osama Bin Laden. Bary, whose music has featured on Radio 1, is one of six children of Adel Abdul Bary, 53.

Bary Snr was extradited from Britain to the US 14 months ago after an eight-year legal battle that made him a cause celebre of the Left as lawyers took his publicly funded case to the European Court of Human Rights in Strasbourg.

Investigators believe Bary Snr was one of Bin Laden’s closest lieutenants in the infancy of Al Qaeda and ran a London cell of the terror network. He faces life in prison if convicted of involvement in the bombings of US embassies in East Africa in 1998.

His son’s appearance among the ranks of UK jihadists in Syria, where several Britons fighting for the militants have already been killed, will add to concerns about their potential threat to the West.

Bary lived with his mother Ragaa for more than a decade in a home in Maida Vale, West London, owned by Westminster Council. If it were sold on the open market it would be worth £1 million.

She travelled to Britain from Egypt in 1990 after her husband was granted refugee status.

Friends said Bary’s conversion to radical Islam happened as he grew increasingly frustrated with the British authorities over the wars in Iraq and Afghanistan. And it came despite his fledgling success on the underground grime music scene, where he rapped under the names Lyricist Jinn and L Jinny.

Bary appeared in dozens of videos, including one in which he posed outside the Bank of England and declared his allegiance to the global hacking group Anonymous.

On July 1, he announced that he was turning his back on music as “I have left everything for the sake of Allah”. It is understood that soon afterwards he travelled to Syria, where one of his oldest friends had already joined the fighting.

He changed his Twitter name to Soldier of Allah and posed for pictures wearing a mask and military fatigues while carrying an AK-47 and other large assault rifles.

Last month he said, “Oh Allah, grant us martyrdom” and praised Bin Laden, calling him a ‘lion’. Referring to conditions in Syria, he said it is the “real jungle out here”.

A Metropolitan Police spokesman refused to confirm whether the force’s counter terrorism unit is aware of Bary’s trip to Syria or his violent internet boasts.

•Text excerpted from Daily Mail. Photo shows Bary, the rapper-turned-terrorist.