A major review into the positioning of “mature readers” graphic novels has taken place across Herts libraries after a mum complained about explicit images being easily accessible at the Harpenden branch.

The titles, which are aimed at adults because of their explicit or extreme content, were displayed on the other side of shelves holding children’s books, and mixed up with a range of all-ages publications featuring the likes of Superman and Spider-Man.

Harpenden resident Louisa de Beaufort, who has two children under the age of 10, said: “Within 10 minutes of browsing a selection of these graphic novels, I found myself looking at realistic depictions of rape and women being sexually humiliated and degraded.

“These publications were displayed at the height of a toddler on the other side of the shelving holding children’s books. I took out 10 of these graphic novels on my children’s library cards to test if the library would issue these to children via the self-service machine.”

Books she withdrew included the superhero satire The Boys, supernatural horror series Fatale, and titles from DC Comics’ mature readers Vertigo imprint such as Crossing Midnight and Tokyo Days, Bangkok Nights, none of which are intended for minors.

She said she was disappointed by her findings: “I haven’t lived in Harpenden long and the library has been such a lifeline to me that I just felt so incredibly sad I cannot let my children go anywhere without supervision.

“I feel we have already lost the battle with the internet, and now we have lost it with the libraries.”

Louisa is a supporter of the national Child’s Eyes campaign aimed at keeping extreme images away from children, and added: “I am not calling for censorship, but if they are going to stock these books then the library staff need to know what is in them.”

A spokesperson from Herts County Council said: “Hertfordshire libraries provide an extensive range of titles representing a wide range of views, opinions and reading tastes. It is not our policy to display graphic novels for adults alongside books aimed at children.

“Following a recent complaint at Harpenden library that these books had been sited in an area easily accessible by children, we have reviewed the location of graphic novels in all Hertfordshire Libraries to ensure that they are appropriately positioned.

“We have also improved security for the computer system to prevent adult graphic novels being borrowed by under 16s, and to ensure returned items are not placed where children can access them.”

Derek Watson, owner of Chaos City Comics in St Albans, added: “It’s a popular misconception in this country that comic books are just for kids when the reality is completely the opposite.

“The rest of the world has long embraced the comic book as a medium for an adult readership as well as one for children, and now, in recent years, we in the UK are adopting the same attitude.

“Comic books are not just colourfully-illustrated stories involving ‘men in tights’, they are just like regular full-print novels.

“I have to say that I’m slightly surprised that adult-themed books were displayed alongside all-ages ones at Harpenden library.

“Up until recently we supplied all of Hertfordshire with their graphic novels and collected comic book stories.

“Both the libraries buying team and ourselves were always keen to identify those books that contained mature themes, so I can only assume that there has been a breakdown in communication at local library level.”