A writer has sued 20th Century Fox for copyright infringement, alleging that its 2014 production, Kingsman: The Secret Service, was based on a screenplay he wrote in 2003 and not on a Marvel-owned comic book as was claimed. R Spencer Balentine has sought damages of at least $5 million, according to The Hollywood Reporter. The publication said Fox has not responded to a request for a comment.

The spy comedy film, directed and co-written by Matthew Vaughn, is officially an adaptation of the Kingsman comics franchise written by Mark Millar and Dave Gibbons and published by Icon Comics, an imprint of Marvel. Kingsman: The Secret Service starred Samuel L Jackson, Colin Firth, Mark Strong and Michael Caine. A sequel, Kingsman: The Golden Circle, was released in 2017.

Balentine alleged his screenplay, titled The Keeper, attracted Marvel’s attention when it featured as one of 10 best entries at a screenwriting contest in 2004. The screenplay was considered for adaptation as a comic book by Dabel Brothers Productions. The complaint alleges that Dabel and Marvel entered into a publishing and distribution agreement in 2006, which gave Marvel access to his work.

Balentine claimed that there were striking similarities between his screenplay and the film, particularly with regard to the characterisation. He alleged that the similarities range from the upbringing and beverage choice of the characters to disdain for humanity and vulnerability to panic attacks.

“The Film is purported to be based on a comic book series originally entitled The Secret Service, first published in 2012 by Icon Comics (a division of Marvel) and written by Mark Millar,” attorney Steven Lowe wrote in the complaint. “However, several key aspects of the Film do not appear in The Secret Service comic that do appear in [Balentine’s] Screenplay; for example, in the comic, there is no reference to Knights of the Round Table, no small dog companion to the protagonist, no use of holograms, and the general theme of the comic is about public service rather than an individual overcoming humble origins to achieve greatness.”

Kingsman: The Secret Service (2015).