If you thought Space Cadets was the pits, just wait for the new Channel 4 reality show

Forget witchetty grubs, high-wire trials and Space Cadets. Try convulsions, vomiting and gut-wrenching pain. Channel 4 is to screen a brutal, live reality-style series in which viewers will see heroin addicts going "cold turkey" as they try to come off the drug.

The station and producers believe the week-long series will act as a stark warning to viewers about the dangers of getting involved with the drug when it is shown in the New Year. Cameras will be placed within a treatment clinic and follow at least three addicts as they go through withdrawal with twice-daily programmes.

But critics say exposure on television could leave the addicts vulnerable in the vital weeks after the detox when they will need a strong support network.

Programme-makers will not be searching for addicts. Those featured will already be signed up to start a programme and will have to give consent to appear on television. Co-executive producer Nick Curwin said: "Anyone tuning in thinking this is going to be entertaining will be sorely disappointed. This is one of the most brutal experiences known to man. It is going to be extremely tough to watch and if you are just looking for a bankable TV hit, you wouldn't be commissioning it. It's very brave.

"The basic principle is that we want to show what the experience of coming off heroin is like. The point is to show the kind of grip it has over people, not just the addicts but their families and friends. We wanted to be able to show it in a clear and visceral way, and doing it will be as campaigning, without being worthy, as we can possibly be."

The series, yet to be given a name, was initially commissioned as an educational programme for morning screenings, but Channel 4 chiefs have decided to schedule post-watershed shows as well. A documentary will later be screened to examine the long-term success of the withdrawals.

"There will be all sorts of challenges for us because some of the programmes will be going out in the morning. Although we want to give young people a very good, clear, visual appreciation of what all this is about, we also need to take care," said Mr Curwin, the joint managing director of Firefly productions which is making the show. His firm's past projects have included Anatomy for Beginners in which Günther von Hagens dissected corpses on screen.

There are around 60,000 registered heroin users in the UK, according to figures released this year. During withdrawal, addicts experience symptoms such as tremors, muscle cramps, diarrhoea and insomnia, usually peaking two to three days after their last hit.

John Beyer, director of campaigners Mediawatch UK, applauded the aims of the programme. "Drug abuse is a very serious problem, and if they can persuade people not to take drugs it can be a good thing," he said. "But what bothers me most about it is that on the one hand they say they want to show the reality of drug abuse and then on the other they show movies which tend to glamorise their use."

A spokeswoman for the drug and alcohol treatment charity Addaction said: "I do hope it is not exploitative but I have concerns about the programme. I hope that individuals are not made more vulnerable. It is not just about withdrawal: it is about what happens to them afterwards, the support they get."