There is nothing unusual about a footballer being sent marriage proposals, women's underwear and letters smudged with lipstick. Fan mail is part and parcel of Premier League life. But when that footballer is a convicted child sex offender sentenced to a six year jail sentence? It’s downright disturbing.

Yet it has been claimed that Adam Johnson has been receiving letters from women ever since he was convicted of sexual activity with a 15-year-old girl. According to The Daily Star, the 28-year-old is sent hundreds a week from teenagers to older women. There are even groups on Facebook where women are supporting him.

“There seems to be an unusual attraction,” says Ian Stephens, a forensic psychologist. “It’s not the kind of thing you have the average person doing. I don’t think we find men writing to women in prison who have been involved with this sort of crime.”

The phenomenon whereby people develop romantic attachments with prisoners already exists. It's called hybristophilia, and typically sees women fall in love with serial killers, murderers or violent men. Research in this area suggests these women are seeking protection from the object of their affections, and are attracted to what they see as their ‘alpha male’ behaviour.