The UN's committee on human rights has just published a report criticising Britain's anti-terror laws and the resulting curbs on civil liberties. For many commentators the issues raised are mostly a matter of academic abstractions and speculative meanderings. For me, it is anything but. These laws have destroyed my life.

On May 14 I was arrested under section 41 of the Terrorism Act - on suspicion of the "instigation, preparation and commission of acts of terrorism": an absurdly nebulous formulation that told me nothing about the sin I had apparently committed. Once in custody, almost 48 hours passed before it was confirmed that the entire operation (involving dozens of officers, police cars, vans, and scientific support agents) was triggered by the presence on my University of Nottingham office computer of an equally absurd document called the "al-Qaida Training Manual", a declassified open-source document that I had never read and had completely forgotten about since it had been sent to me months before.

Rizwaan Sabir, a politics student friend of mine (who was also arrested), had downloaded the file from the US justice department website while conducting research on terrorism for his upcoming PhD. An extended version of the same document was also available on Amazon. I edit a political magazine; Rizwaan regularly sent me copies of research materials he was using, and this document was one.

Within hours of my incarceration I had lost track of time. I often awoke thinking I had been asleep for days only to discover it wasn't midnight yet. My confidence in the competence (and motives) of the police ebbed away. I found myself shifting my energies from remaining cheerful to remaining sane. In the early hours, I was often startled by the metallic toilet seat, crouched in the corner like some sinister beast.

For days on end, I drew cartoons and wrote diary entries in the margins of Mills and Boon novellas. I spent hours reciting things to myself: names of Saul Bellow characters, physics Nobel prize winners, John Coltrane albums, anything to keep the numbness away.

I'm constantly coming across efforts being made to give detention without charge the Walt Disney treatment: the crushing weight of solitary confinement is painted as a non-issue; the soul-sapping nothingness of the claustrophobic, cold cell is portrayed as a mild inconvenience. Make no mistake: the feeling that one's fate is in the hands of the very people who are apparently trying to convict you is, without doubt, one of the most devastating horrors a human being can ever be subjected to. It is (to misquote Carl von Clausewitz) the continuation of torture by other means.

"Those who have nothing to hide, have nothing to fear," goes the tautological reasoning of the paranoia merchants calling for harsher, ever more draconian "security" measures - as we saw throughout the 42-days debate. They should read Kafka: nothing is more terrifying than being arrested for something you know you haven't done. Indeed, it is the innocent who suffers the most because it is the innocent who is tormented the most. The guilty calculates, triangulates, anticipates. The innocent doesn't know where to start. The answers and the questions are absolute, unbreachable, towering conundrums.

I underwent 20 hours of vigorous interrogation while entire days were being completely wasted by the police micro-examining every detail of my life: my political activism, my writings, my work in theatre and dance, my love life, my photography, my cartooning, my magazine subscriptions, my bus tickets.

Aspects of my life that would have been seen as commendable in others were suddenly viewed as suspect in my case for no apparent reason other than my religious and ethnic background. I was guilty of being that strangest of creatures: a Muslim who reads; who studied engineering yet writes about Bob Dylan; was a vocal opponent of the Iraq war yet owns all of Christopher Hitchens' writings; admires Terry Eagleton yet defends Martin Amis; interviews Kazuo Ishiguro, listens to Leonard Cohen, goes to Radiohead concerts, all of which became the subject of rather bizarre questioning.

This is not all: outside, lives are shattered, jobs are lost, marriages are destroyed, minds are damaged, friends and families are traumatised - often irrevocably so. My parents, whom I wasn't allowed to call, could barely get any sleep throughout the ordeal. Many of my Muslim university friends were, and still are, worried about being targeted themselves. For most of my loved ones, despite my innocence, nothing will ever be the same again. I'm now jobless, facing destitution and threatened with deportation from the country I've called home for nearly half my life.

Immense pressure is exerted on law enforcement agencies by their political mandarins to produce "results": pressure to produce a higher number of arrests but also the corollary, more dangerous, impulse to justify them at any cost. Naturally, through a perverted but pervasive circularity in the logic, lack of evidence becomes the very justification for requesting "more time". The government claims that checks and balances will ensure extensions to detention periods are based on verifiable and compelling arguments. I beg to differ: in my case, the judge was simply bullied by streams of technospeak until she had no option but to grant extra time.

Fighting terrorism is a serious matter and needs to be tackled in a serious way - not through empty gimmicks sustained by fear-mongering and alarmist rhetoric. The real danger is that we are witnessing a slide from the essential purity of habeas corpus into a Britain where the innocent are detained until proven guilty.

· Hicham Yezza, an activist and writer, was released without charge after six days in custody, immediately rearrested on immigration charges and issued with a removal order to Algeria, after which he was held for a further 27 days; he is still awaiting a conclusion to his deportation case freehicham.co.uk

· This article was amended on Tuesday September 2 2008. A document known as "the al-Qaida training manual" does not appear on the reading list for Nottingham University's politics department, as we first said in this piece. This has been corrected.