SOME call centres still resemble "satanic mills", despite moves to improve working conditions and help staff who have to deal with abusive customers, a report has found.

Research commissioned by the Health and Safety Executive found that many workers in the growing sector "were treated like a cog in a machine", with low wages, poor working conditions and highly repetitive duties.

Workers complained about being "tied" to their telephone, unable to take regular breaks and with little autonomy over their working day.

The report lends weight to previous surveys which showed some workers had to raise their hands for permission to go to the toilet and had to deal with calls in less than two-and-a-half minutes.

But the new survey of more than 1,000 call centre employees across the UK also found high levels of satisfaction amongst some staff who said they enjoyed their job.

People working for telecoms and IT companies showed the highest levels of depression and the poorest job satisfaction, the report said.

Christine Sprigg, a lecturer in occupational psychology at Sheffield University who conducted the research, said the least satisfied workers had less control over their work but had high demands made of them.

Workers in call centres in the business sector had the highest levels of job satisfaction.