It may be a holiday paradise to you, but to the locals it's a place of torture

One thing that became poignantly clear was their constant fear that the world outside had forgotten them – that no one knew

The man sitting next to me on the back seat of the Tunis to Hammamet minibus fished inside his shabby jacket and produced an ultrasound picture of his son's left testicle. He and the boy, who sat on the other side exhausted and in discomfort, had just spent the whole day – from early morning to mid-afternoon – in the main hospital at Tunis. As a foreigner perhaps he was hoping that I might have something to add to the diagnosis (I think it was "torsion") of the Tunisian paediatrician. Or perhaps he was just being friendly, like so many of the ordinary Tunisians I encountered.

The man sitting next to me on the back seat of the Tunis to Hammamet minibus fished inside his shabby jacket and produced an ultrasound picture of his son's left testicle. He and the boy, who sat on the other side exhausted and in discomfort, had just spent the whole day – from early morning to mid-afternoon – in the main hospital at Tunis. As a foreigner perhaps he was hoping that I might have something to add to the diagnosis (I think it was "torsion") of the Tunisian paediatrician. Or perhaps he was just being friendly, like so many of the ordinary Tunisians I encountered.

As open and as guileless as the school-teacher I had been with a few hours earlier – the one who had been tortured. Abdelmouman Belanes taught English in the south of Tunisia. The son of a poor family, Belanes joined the PCOT, the Tunisian Communist Party – as once I had joined the British Communist Party. But there was this difference – in Tunisia being an anti-government activist brings you something other than ridicule in the right-wing press or a silly file in a box in a room by the Thames. "How to say this...," Belanes paused and grimaced, after I asked him to describe how he had been tortured by the Tunisian authorities.

Well, first they beat him with their fists on his head and his whole body. Then they administered electric shocks (his eyes widened as he recalled the experience) in the usual places. Next they trussed him up in the agonising position known as "the chicken" where the prisoner's hands are tied beneath his thighs, as he is suspended from a bar behind the knees (the cramps are particularly severe). Finally they suspended him upside down over a tank of water, and dipped him in until he was sure that he would drown. They did it "many times".

Abdelmouman's was not the only torture story that I heard that week, as I sat interviewing dissidents in a lawyer's office in central Tunis. I met men, women, student activists (as I once had been), the relations of prisoners, all telling similar but different stories of imprisonment, abuse, harassment, secret police surveillance. And in every case this was being carried out to prevent activities that, in Britain, are perfectly legal.

I had gone to Tunisia as part of a television programme on human rights in holiday destinations. The idea was to reveal the unpleasant things that tourists never see and are rarely told about. In other words, to spoil people's holidays. Yet before the producers asked me to travel to Tunisia I had no knowledge whatsoever of what had been going on there, and not much interest in the place.

Even so, the briefing for the journey stressed that it was mildly hazardous. Other journalists had been beaten up, and – more importantly – their cameras and film confiscated. So we evolved an elaborate back-plot, travelling with a small digi-cam, and getting other people to ferry the material back to Britain. The Tunisian government most certainly did not like people like Abdelmouman being interviewed.

Almost everywhere we went we were aware of the secret police. Going in to see a human rights activist in a large building meant passing fat men in camel-hair coats standing in shop doorways, brushing past younger slimmer men in leather jackets, leaning on parked cars, avoiding the glances of sunglassed 20-year-olds in Nike tops – all of them there ostentatiously to spy and to harass.

The office of the human rights lawyer, Radhia Nasraoui, was in a large block, and it was difficult for the police to see who was going in and out. It was there, sitting on her rickety furniture (the first and second lot were confiscated after raids), that we met the victims of the Tunisian government's determination to suppress dissent.

One man I didn't meet, however, was Radhia's husband and father of her three daughters, the PCOT leader, Hamma Hammami. At that point he was in hiding, sentenced to nine years in prison for his activities. The sentence was made up of a year here and six months there for such crimes as handing out unauthorised leaflets, meeting in an unauthorised place, publishing slanders about the state, spreading false news and undermining the authority of the judiciary (by criticising it).

Hammami, who has himself been tortured, came out of hiding while we were in Tunis, and is now back in prison. I've met his middle daughter, who is the same age as my eldest. It makes you want to weep.

As you can imagine, a regime as sensitive to criticism as that of Tunisia goes to substantial lengths to prevent objective reporting. As a result of harassment and the rather arcane laws (such as the offence of spreading false news), the press is supine and self-censoring. And extensive measures have been taken to prevent the infiltration into Tunisia of cyber information. Only two internet service providers are permitted, both run by people with close ties to the family of the President, Zine El Abidine Ben Ali. This summer a young journalist, Zouhair Yahyaoui, who had set up a website called TUNeZINE, was arrested in a Tunis cybercafe. His home was searched, and he was tortured by being made to hang from his arms, with his feet barely able to touch the ground. On 20 June, as thousands of tourists arrived on the Tunisian coast, he was given a 28-month sentence for, inter alia , "unauthorised use of an internet connection".

What do the Western powers make of all this? On 19 March 2001, Senator Joseph Lieberman paid tribute to Tunisia on the 45th anniversary of its independence. According to Lieberman "the United States and Tunisia have shared a mutual commitment to freedom, democracy, and a peaceful resolution of conflict". Recently a State Department spokesman praised Tunisia as "a strong supporter of our campaign against terrorism". Unbelievably, in 2005, Tunisia will host the World Summit on the Information Society under the patronage of the United Nations secretary-general Kofi Annan. That should be interesting. As interesting, in fact, as the succession to the chairmanship of the UN Human Rights Commission next year of Tunisia's neighbour, Libya.

Governments do what they do. But there was one thing that became poignantly clear as I talked to the sacked journalists, the tortured teachers, the wives of the imprisoned and their children, and that was their constant fear that the world outside had forgotten them – that no one knew. It's little wonder then that a visit from a friend who works for Amnesty, or even an article like this one, gives some strength to the persecuted. Even better, however, would be the knowledge that hundreds of citizens in a country far away, but well respected, had taken the time to write on their behalf or to write directly to them. Their addresses are all available from Amnesty International, which is one of the organisations – and I can attest to it – that saves lives.

David.Aaronovitch@btinternet.com

" Paradise Exposed" will be shown on BBC2 on Sunday at 7.10pm