Scientists at the University of Montreal launched a search for men who had never looked at pornography – but couldn’t find any.

Researchers were conducting a study comparing the views of men in their 20s who had never been exposed to pornography with regular users.

But their project stumbled at the first hurdle when they failed to find a single man who had not been seen it.

“We started our research seeking men in their 20s who had never consumed pornography,” said Professor Simon Louis Lajeunesse. “We couldn’t find any.”

Although hampered in its original aim, the study did examined the habits of those young men who used pornography – which would appear to be all of them.

Prof Lajeunesse interviewed 20 heterosexual male university students who consumed pornography, and found on average, they first watched pornography when they were 10 years old.

Around 90 per cent of consumption was on the internet, while 10 per cent of material came from video stores.

Single men watched pornography for an average of 40 minutes, three times a week, while those in relationships watched it 1.7 times a week for around 20 minutes.

The study found that men watched pornography that matched their own image of sexuality, and quickly discarded material they found offensive or distasteful.

Prof Lajeunesse said pornography did not have a negative effect on men’s sexuality.

“Not one subject had a pathological sexuality,” he said. “In fact, all of their sexual practices were quite conventional.

“Pornography hasn’t changed their perception of women or their relationship, which they all want to be as harmonious and fulfilling as possible,” he added.