For millions of people in the UK, anti-terror legislation is rather distant, its finer points discussed only by politicians, specialist lawyers and the like. We hear about attempts to introduce tough laws; we hear about new arrests, and we get on with our lives. But for my friend Hicham and me, the force of the new anti-terror legislation suddenly became a harsh reality. Our arrests have implications for the rights of individuals in Britain to read legally available open-source documents free from the fear of arrest.

May 14 2008. A postgraduate international relations student at the University of Nottingham and a principle administrator in the modern languages department (also a former postgraduate student at the university), Rizwaan Sabir and Hicham Yezza, were arrested under section 41 of the Terrorism Act 2000. I type this sentence, and despite everything, I still find it difficult to comprehend the arrests. We were detained for six days, unable to see our family or friends on suspicion of being involved in the "commission, preparation, or instigation" of an act of terrorism. Our homes were raided and my terrified family evicted from their home.

The operation, codenamed Minerva, was led by the West Midlands counter-terrorism unit and involved 26 police officers, forensic experts, three police raids, and thousands of pounds of hard-earned taxpayers' money.

After failing to find justification to detain me any longer, on day six of our ordeal, I was released without a charge, without an apology; but with a police warning against accessing an openly available, widely cited al-Qaida document considered relevant to my postgraduate research by me and my academic supervisors. I was only put under threat of future arrest, but Hicham's terrifying detention was prolonged by the authorities, under immigration charges – his ordeal continues to this very day.

What was our offence?

Our offence was that we had in our possession an edited version of a document referred to as the "al-Qaida training manual". A document freely available on the US Department of Justice website and that of the Federation of American Scientists. A document widely available elsewhere on official and unofficial internet sites, in either edited or full versions. A document purchasable in paperback from Amazon. A document I had downloaded months ago for my masters dissertation and upcoming PhD. A document a lecturer knew I was consulting. A document I had sent months ago to Hicham who was helping me draft my PhD proposal. A document many other academics and students studying terrorism will have had in their possession. A document extensively cited in books on terrorism. A bog-standard source. Nothing extraordinary or remarkable about its possession – one would think.

Once placed under arrest in the car park of the University's Trent building, I naively thought I would be released in a few hours, that it was all a terrible misunderstanding or a sick joke.

We were taken to Bridewell police station (a small specialised prison complex consisting of approximately 90 cells) and placed in a cell. I was informed that a warrant would soon be issued and my house would be raided. I had still not been told the reason for my arrest.

For the suspected "terrorists" (Hicham and me), they had sealed off the entire second floor of the prison. We were kept in solitary confinement. Our only human contact – apart from the detention officers and my lawyer – was with a judge that smiled down on us whilst stamping an authorisation order for a further five days detention.

For the first 12 hours I was incommunicado. For the first 2 days I was on a 24-hour watch. Two officers sat outside my open cell door, watching my every move and making notes in a custody log. I couldn't sleep. I couldn't eat. I was too scared to pray, lest that be used against me. My property was seized, forensically examined, and my family evicted. My car was compounded and my friends and lecturers repeatedly questioned. I was photographed, fingerprinted, foot-printed and DNA-swabbed. It was the first time in my life I had felt so criminalised and degraded.

I was interviewed once a day, except for the last day, when I sat through two mind-numbing interviews. I was asked my opinion of the training manual, whether I had used it, or was planning on using it, or whether I had disseminated it. I was asked if I had ever travelled to Pakistan, Iraq, Afghanistan or Turkey (obviously the lack of stamps in my passport weren't enough to convince them), whether I had ever been camping, or was planning a camping trip. I was questioned about September 11 and asked to explain what I thought of al-Qaida. The interviews got more absurd with time. I was questioned about journal articles in my bedroom from Foreign Affairs and World Politics, photographs I had taken of friends with Edinburgh Castle in the background, and questioned about cheesy pop CDs from the early 1990s – embarrassingly – discovered in my bedroom.

Unfettered questioning and microscopic searches for six days did not produce any evidence, and I was released without charge. The police had finally realised I was a postgraduate student studying terrorism; not a member of an al-Qaida sleeper-cell.

Bill Rammell, the higher education minister, has made it clear, in his speeches and through his department's guidance to universities, that academic freedom is important and that it is vital that academics and students should be able to study terrorism. Nevertheless, in apparent contravention of the government guidance, the police threatened me with further detention if I used the document for my research.

I would like to say my freedom to research had the full backing of my University authorities, but unfortunately they appear unwilling to uphold the right of their students to read and study legal, openly available documents free from the fear of arrest.

My feeling upon release was sheer relief and happiness; the joy of freedom and the pleasure of seeing my loved ones was something I had never encountered before. But beneath it all lay terrifying thoughts and questions; what would have happened if I had been charged? How would I have coped in a maximum-security prison? The answers to these questions still haunt me today.

The authorities have a tough job fighting terrorism. But locking away innocent people without prior investigation (for what may soon be 42 days) to later release them without charge is certainly not the way. It is not the way to make Britain safer. It is not the way to bring a multicultural and multiracial society together. It is not the way to unit British citizens against terrorism, but it is a way of setting a very worrying precedent that might achieve just the opposite.

Detaining people who have actually committed a crime of which there is evidence is understandable, but detaining those against whom there is no evidence is not.