A radical Muslim student who wanted the black flag of Isis to fly over Downing Street is facing jail after being found guilty of planning to join rebel forces in Syria.
David Souaan, 20, wept in the dock as he was convicted of preparing for terrorist acts in the war-torn country following a trial at the Old Bailey.
The prosecution said he had visited Syria in December last year and was on his way back to fight the jihadist cause when he was arrested at Heathrow Airport on May 31.
The Birkbeck College student, who comes from a wealthy family in Serbia, denied the charge and insisted his earlier visit to Syria was to collect his grandfather's belongings.
Judge Peter Rook ordered pre-sentence reports and adjourned sentencing until Tuesday February 3.
Remanding Souaan in custody, he said: "You have been convicted of a very serious offence indeed. You must understand that you will be receiving a custodial sentence in this case."
Souaan, the son of a Serbian Christian mother and Syrian Muslim father, grew up in his mother's country but had close family ties to Syria and had adopted his father's religion.
He came to the UK last year on a three-year visa to study global politics and international relations at Birkbeck College in London, living in halls of residence in Malet Street.
He was arrested after fellow students became concerned at his radical views on Islam and he showed off pictures of himself posing with guns.
Police seized his laptop and phone and found pictures, videos and documents revealing his "extremist sympathies" and that he had not only been fighting in Syria before but was intending to return, the Old Bailey heard.
Prosecutor Sarah Whitehouse QC said one video clip on his phone was "so graphic and so shocking" that it could not be played in court.
It featured a young-looking man kneeling with his head held back as another man cut his throat.
The court heard that Souaan filmed himself attending a demonstration in the UK.
Mrs Whitehouse said that a man - probably Souaan - could be heard in the background saying: "The flag of Tawheed in London, all praise be to Allah the lord of the universe," in reference to the wish of Muslim extremists to see the black flag fly over Downing Street.
In his defence, Souaan told jurors he had accompanied his father to his home town of Deir ez-Zor in Syria for two nights in December last year.
He said he went to help retrieve his 82-year-old grandfather's belongings after he fled to Turkey with just the clothes on his back.
He posed for pictures with guns because he wanted to look "cool", he said: "At the time when I was there I felt something like I wanted some trophy - the photos.
"As the teenagers say nowadays, it looks 'cool'. So that was the reason."
Souaan, whose father made a fortune in the construction business in Serbia, insisted that, while he was in the town held by the Free Syrian Army, he never had a weapon.
He said he had been lonely in London after arriving for his first term of university on October 6 last year.
He kept in contact by text with his Christian Serbian girlfriend who had gone to Miami to study.
She called him by his pet name "little panda" and he told her he loved his "little sweetie... more than anything in the world".
The jury took nine hours to find Souaan guilty.
Afterwards, Commander Richard Walton said: "Souaan had an active interest in Syria and was set on fighting there.
"I'd like to thank those around him that reported his change in behaviour and extremist views. By coming forward, we were able to prevent him travelling and engaging in terrorist activities."