Psychologists at the family and personal relationships laboratory at the university studied 40 top box office hits between 1995 and 2005, and identified common themes which they believed were unrealistic.

The university's Dr Bjarne Holmes said: "Marriage counselors often see couples who believe that sex should always be perfect, and if someone is meant to be with you then they will know what you want without you needing to communicate it. We now have some emerging evidence that suggests popular media play a role in perpetuating these ideas in people's minds. The problem is that while most of us know that the idea of a perfect relationship is unrealistic, some of us are still more influenced by media portrayals than we realize."