A "tech-savvy" teenager who uploaded masses of child and animal pornography to the internet could face jail after a court threw out his claims he did not mean to access the material.

Dilruk Dias-Banbaranayake, 18, stored hundreds of vile images and videos - including one that showed sexual activity between a dog and young girl - on his online Dropbox account after being sent them via a mobile chat app.

The Selsdon teenager, who was just 15 when he first uploaded the illegal material, claimed he signed up to the Kik app because he was "bored" and there was "trouble between his parents" - not to receive indecent images.

He told magistrates at Croydon Youth Court today that "complete strangers" had sent him nearly 500 sick photos and videos in messages between February and July 2014 after he posted his Kik username in an online chat room.

In one of the most disturbing videos found on Dias-Banbaranayake's Dropbox, described to the court by Detective Constable Sue Day-Sawyer, a three-year-old girl cries as she is raped by a man in front of the camera.

The student, who is believed to study at Kingston College after previously attending Wimbledon College, protested his innocence and claimed he had not realised the images were being sent to him.

He claimed his Android phone was automatically backing them up to his Dropbox account along with holiday snaps from Venice and Rome.

Watched by his parents in the public gallery, Dias-Banbaranayake, of Addington Road, said he deleted all the illegal material from his phone as soon he realised what had been sent to him, but was not aware the images were still stored on Dropbox.

But chief magistrate Terry Geater said it was "inconceivable" the "tech-savvy" teenager had not been aware of the images or that he had been sent so much material unsolicited.

Dias-Banbaranayake was found guilty of 12 counts of possessing extreme or indecent material and immediately placed on the Sex Offenders Register.

He was released on conditional bail until a pre-sentence hearing at the youth court on June 2, at which magistrates will decide whether the teenager should be sentenced by a judge at crown court.

Dias-Banbaranayake said he had no comment for press as he left the court room with his parents today.