Dozens of anti-terrorist investigations and prosecutions are in jeopardy after senior judges yesterday quashed the convictions of five young Muslims for downloading extremist propaganda. Three Court of Appeal judges, led by the Lord Chief Justice, questioned whether they should ever have been prosecuted for merely possessing the material. The ruling means that in future the prosecution will have to prove that defendants intended to commit terrorist attacks.

The men, four university students and a schoolboy, who ran away from home saying that he wanted to die fighting jihad, are the first people to have convictions for Islamist terrorism overturned since the War on Terror began in 2001. The judges ordered that Irfan Raja, 20, Awaab Iqbal, 20, Aitzaz Zafar, 21, Usman Malik, 22, and Akbar Butt, 21 – who were in the dock to hear the judgment – be freed immediately. Three hours after the judgment was handed down, the five men walked out the front door of the court.

Mr Butt said: “Whatever happened has happened and I’m just happy to be out now. I won my freedom back.”

The judges’ ruling dealt a severe blow to the body of anti-terrorism legislation in Britain by rewriting two key sections of the Terrorism Act 2000. Sections 57 and 58 – which outlawed the possession of items likely to be of use or connected to terrorism – have been used by police and prosecutors to spearhead the fight against the radicalisation and recruitment of young Muslims.

The police regard the sections as a means of intervening early to prevent potential recruits going over seas to wage jihad or to receive terror training.

Continuing investigations will be urgently reviewed, cases awaiting trial under the legislation may have to be abandoned and a number of people convicted of terror offences, including Samina Malik, the so-called Lyrical Terrorist, are expected to lodge appeals.

Detectives said that the five men freed had large collections of extremist material and were planning to travel to Afghanistan to wage jihad.

Mr Raja left a farewell note for his parents and said that he would see them in Paradise. The trial judge said that the men had become “intoxicated” by extremism.

But human rights lawyers and Muslim community leaders claimed that no evidence of a terrorist plot had been uncovered. They argued that the Terrorism Act 2000 had been used to criminalise young people simply for harbouring radical thoughts.

The appeal court described the terror legislation as imprecise and uncertain and said that it allowed police to define terrorist offences far too widely.

The judges ordered that, in future cases, the Crown would have to prove that defendants clearly intended to engage in terrorism or that the items they possessed were of practical use to a terrorist.

They said the intention of the legislation had been to criminalise possession of items that might be used in making a bomb. The appellants, however, had only possessed literature.

The judgment said: “Literature may be stored in a book or 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 Crown Prosecution Service said that it was studying the judgment and considering an appeal to the House of Lords.

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