Muslim extremist David Souaan has been jailed for three and a half years after taking up arms alongside rebels in Syria and vowing to fly the black flag of the so-called Islamic State (Isis) above Downing Street.

The 20-year-old student, who comes from Serbia and studied at Birkbeck College, London, visited Syria in December 2013 and posed for photos with a Kalashnikov gun.

He was arrested at Heathrow Airport in May last year before he could commit jihad on the streets of the capital and was found guilty in December.

Souaan originally came to the UK in 2013 on a three-year visa to study global politics and international relations at Birkbeck College in London.

He lived in the halls of residence in Malet Street but his peers became concerned about his extreme views when they saw photos of him in Syria.

During his trial at the Old Bailey jurors heard how he shunned his mother's Christian faith to adopt Islam, which his wealthy industrialist father followed.

Denying the charges, he told the court he and his father had travelled to his home town of Deir ez-Zor in Syria in December 2013.

Police found pictures, videos and documents revealing "extremist sympathies" on his phone and laptop, with one of the videos - of a man having his throat slit - so graphic it could not be showed to the court.

Souaan's sentencing follows that of Portsmouth jihadist Mashudur Choudhury, who became the first Briton to be sentenced for fighting in Syria.

A member of the "al-Britani Brigade Bangladeshi Bad Boys", Choudhury was described as "ideologically confused" during his trial and was handed a four-year prison term.