For over a century, people have been predicting that technology would give us more free time: we could eat pills instead of cooking, robots would clean our houses, the Internet would mean none of us would have to waste time travelling to work. Technology would also solve other nasty problems, so no-one would have to do dangerous, dirty or dull work to earn money. That was the prediction! Sadly, it's not quite worked out that way.

In many countries, people are working more hours than fifty years ago. Some terrible jobs may have disappeared: for example, we don't make the colour purple with rotting seafood anymore! However, there are still plenty of bad jobs left - jobs in which you may risk injury, be exposed to chemicals and dirt or maybe just die of boredom!

1 HUMAN GUINEA PIG

Hundreds of people take part in drug trials every year.

For between €45 and €4,500, they take a new drug to test for any side effects, such as vomiting or headaches. Some students join these drug trials as a relatively quick and easy way of earning money. John Spiral, a history student from Dublin, regularly does them. 'You might go to the hospital three or four times, maybe eight hours 'work'. I had a really upset stomach once, and another time I got strange red marks on my skin, but that's all. Usually it's fine, and you're helping science, which benefits everyone!'

2 EMBALMER

Embalmers preserve dead bodies in preparation for funerals. They work anything up to 50 hours a week for a salary of around £15,000 a year, far less than the national average. They spend most of the day on their feet and generally work bent over a table. They also have to work with very strong-smelling chemicals. I suffer from backache, but the job's not as bad as you might think,' says Frank McCreary. I'm even used to the smell now - I don't even notice it. And of course the families of the dead are usually very grateful for the job I've done, which is obviously a big motivation for me.'

3 CALL CENTRE WORKER

Many banks and other companies have call centres abroad where customers can ring for information or to complain.

Levels of stress among workers are very high. They often work in cramped conditions, have to stare at a computer all day, and have little opportunity to laugh or joke with their co-workers.

One worker, from an Indian call centre, said, 'We get quite a lot of abuse. I can't repeat what some people scream at us. Often there is nothing you can do about their complaint, so they slam down the phone, but then you have no time to think before another person calls you straightaway. I don't think I'll ever get used to it. I'd like to leave, but the money's quite good and there's a lot of competition for jobs here in Mumbai.'

4 RECYCLING PLANT WORKER

You're supposed to sort your own rubbish and put glass in one bag, paper in another, but unfortunately many people still don't do this. So workers in a recycling plant have to find the recyclable items from a big pile of rubbish, and all for the minimum wage. You're just dirty all the time and you go home smelling,' says Solomon Iwenofu, an ex-plant worker. 'I got used to it after a while, but my wife never did!' Apart from the smell, there are dangers in handling everything from dirty nappies to rotting meat and used syringes. 'I got on really well with my co-workers and we often joked about things we found, but we also knew you can get hepatitis or other serious illnesses if you're not careful. Luckily for Solomon, it was only a temporary job.

'It helped me when I first came to America, but I always knew I could do better for myself and my family.