They are protesting against two pieces of legislation. The first, the Criminal Justice and Immigration Act, comes into force later this month.
It will make possessing "extreme pornography" - defined as any "extreme image" produced "solely or principally for the purpose of sexual arousal" - illegal.
The Government defines an "extreme image" as any "grossly offensive, disgusting or otherwise ... obscene" moving or still depiction of someone any "reasonable person" would think real being sexually injured or engaging in sexual activity with an animal or corpse.
Films given an official classification are exempt from the new law, meaning portrayals of such extreme activity by actors will be allowed on screen. However, imitations by characters on paper will not enjoy such an exemption.
The second is the Coroners and Justice Bill, which is currently passing through Parliament. It will introduce a similar law banning the possession of any image involving sexual activity and children. For the purpose of the law, an image is said to contain a child if "the impression conveyed ... is that the person shown is a child".
The comic book campaigners claim that if the new rules are interpreted harshly, their hobby could be criminalised.
In a statement, comicshopvoice.co.uk,
a comic fans' website, said of the rules outlawing sexual violence: "Isn't that how Batman, Punisher, Judge Dredd get anything done?
"A kick in the balls or a--- would constitute this, and a kick in the balls is a well trodden part of humour."
It added that the new law on images of children would make owning some comic books, and "particularly some forms of Manga" - the Japanese form often featuring young-looking cartoon characters - illegal.
The statement added: "Because this is a minefield for the law it then falls on the Police to enforce it, and it is their judgement that could lead to a prosecution.
"We COULD get to a point where the police could legitimately visit your home or workplace, and sanctioned by an un-elected magistrate or judge go through your collection and if they find any comic book that they feel will cause sexual arousal or displays extreme violence then they could arrest you."
Calling on comic book fans to lobby their MPs, the group added: "What is frightening about this law is that it gives [the Government] carte blanche to invade our lives, to shut down our comic shops and ultimately it could lead to censorship of books and films as well."