A radicalised young supermarket worker from High Wycombe shared Islamic State propaganda on WhatsApp, a court has heard.

Iftikhar Ali was aged 18, living at home with his parents in Totteridge Drive, and had a job at Sainsbury's at the time he allegedly sent extremist material on his mobile phone.

He is on trial at the Old Bailey charged with 12 counts of dissemination of a terrorist document and one of possessing a document likely to be useful to a person committing an act of terrorism.

Opening the case, prosecutor Mark Paltenghi warned jurors that some of the evidence was "graphic" and "upsetting" and showed men about to be killed, although it was edited out of respect for their families.

He said: "The allegations span a period of six months between September 8, 2015 and the defendant's arrest on March 10, 2016.

"It is the Crown's case that although he was young, he had already become a radicalised proponent and supporter of extreme Islamism."

Ali allegedly sent a string of audio files on WhatsApp containing Nasheeds [songs], with titles such as For the Sake of Allah and Give Our Regards to Abu Bakr and Oh Islamic State You Light the World.

Following his arrest, police also recovered an alleged terrorist document entitled Advice for those doing Hijrah [migration], jurors were told.

In a police interview, Ali made no comment to most questions but when asked about the "central plank" of the case, denied ties with IS, the court heard.

He told officers: "I have no links to any terrorist network. I was interested for research and curiosity purposes only as to what was going on in the Middle East. I'm not part of Islamic State or any other organisation."

Mr Paltenghi said it would be for the jury to decide if Ali had an "idle interest" in the Middle East or not.

He went on to tell jurors that Ali's defence would suggest that, at the time, he had another mobile telephone which was not recovered.

Ali, now aged 19, denies the charges against him.