Irfan Raja ran away from his family home in Ilford, East London, in February 2006, leaving behind a note that terrified his mother and father. In neat handwriting he told his parents that they would meet again in Paradise and urged them to “rejoice at the decision of their son”.

His parents had noted his religious strictness and feared that he planned to fight jihad overseas. He had gone no farther than Bradford, however, where he met four university students whom he had been in contact with over the internet.

Three days after he left home Mr Raja, 17, called his family and was persuaded to return. He was arrested by the anti-terrorist unit of Scotland Yard. Detectives also arrested the men they described as his co-conspirators — Aitzaz Zafar and Awaab Iqbal, from Rochdale, Usman Malik, from Wolverhampton, and Akbar Butt, from Southall, West London.

Extremist literature, documents, film clips and jihadi songs were recovered from computers and bookshelves. The men were charged under Section 57 of the Terrorism Act, which states that it is an offence for someone to possess items for a purpose connected with the commission, preparation or instigation of an act of terrorism. They were convicted last July at the Old Bailey and sentenced to terms in prison and youth custody.

There was a furious reaction to the convictions from the Muslim community, particularly about the case of Mr Raja, who many felt was a naive, young man being criminalised for his thoughts and not for any action that he had taken. Defence lawyers started an appeal, arguing that the material possessed by the men was extremist and unpleasant but its possession was not sufficient to prove an intent to undertake a terrorist act.

The Court of Appeal judges, led by Lord Phillips of Worth Matravers, the Lord Chief Justice, noted that the so-called terrorist material was literature and added: “Literature may be stored in a book on a bookshelf, or on a computer drive, without any intention on the part of the possessor to make any future use of it at all.”

The court concluded that Section 57 was imprecisely worded.

The judges also examined an appeal against charges under Section 58 of the 2000 Act, which outlaws possession of information of a kind likely to be useful to a person committing or preparing an act of terrorism. They rejected the overall appeal, referred to only as the case of K, but raised concerns about the unclear wording.

The court called for a review of a number of charges in a high-profile terrorist case that has yet to come to trial.

Mr Raja and his co-appellants had arrived at the Court of Appeal yesterday as prisoners. They left, in the wake of the judges’ ruling, as free men and victims of the first miscarriage of justice case since the events of September 11, 2001.

Mudassar Arani, the solicitor for Mr Butt, said: “His reputation has been tarnished and his education unnecessarily interrupted by these proceedings.”

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