ADAM Johnson was notorious for his love of X-rated films. He had a 'hardcore porn app' on his phone to access material any time of the day - and when police arrested him they found it contained pornographic images of teenage girls.

But any suggestion his obsession with porn could either explain or excuse his behaviour with a 15-year-old school girl is roundly rejected by a Sunderland University lecturer who is a leading expert in pornography.

Professor of Sexual Cultures, Dr Clarissa Smith, said: “Adam Johnson has to take responsibility for his actions. He is not an idiot.

“There is sufficient discourse around about what is appropriate behaviour in sexual matters - that he knew.

“He knew he was engaging, at the very least, in misconduct. We could go further than that.

“I don’t think anyone is under any illusion of that kind and I think we need to step away from the idea there is a single cause for his behaviour.

“He has to take responsibility for what he did – as well as some of the environment in which he might have been encouraged to think that he could act with impunity. That doesn’t come from porn.”

Dr Smith said the case highlights the need for “more conversation about sexual ethics” and equipping young women and men with the right kinds of tools and resilience for engaging in sexual and emotional relationships.

“A lot of this is about emotions. It seems to me, it was about more than sex.

“It was the emotional highs they were getting from their texting and about romance and its upstoppability – that you just give into it, because it feels so overwhelming that it must be genuine. That’s part of our problem.”

Dr Johnson said it was wrong that pornography is seen as the cause of bad attitudes, when it is actually a symptom of wider problems in our culture about gender and sexuality.

“The idea that young men start to see woman as objects . . . that really could only happen if they had no other influences on them at all.

“For example if they didn’t know woman as mothers, sisters and cousins playmates. But they do - and they have other inputs from school, the home and peers.”

She added: “I think that the fact a case like this causes so much controversy and dispute about who is at fault is an indication that some of our ways of talking about particularly young women is very problematic.

“And that doesn’t come from porn it comes from a whole raft of very powerful discourses that operate in our culture – about what constitutes good behaviour what they ought to be doing about parental roles and young men and their predatory attitudes.”

Dr Smith said one must be wary when referring to “extreme porn”, which is used only when there is a particular legal definition.

“Most people are not looking at that kind of material. Images of bestiality have circulated since the year dot. Certainly they don’t circulate as arousal material, but as objects of disgust.”