Two comic-book artists are suing Marvel over an accusation that Iron Man’s body armour has been copied from their original designs, according to the Hollywood Reporter.

Brothers Ben and Ray Lai, run a company called Horizon Comics Productions and claim their 2001 comic-book series Radix features characters who “wear highly detailed, mechanised suits of body armour” which are too similar to those used on screen.

The brothers have previously accused the Massachusetts Institute of Technology of copying their designs in a 2002 illustration concerning body armour for soldiers. MIT made a public apology and the publicity led to Marvel hiring the brothers to work on various comics.

In the official complaint, there are detailed pictures that showcase the many alleged similarities between the designs.

The case comes as Marvel rolls out Avengers: Age of Ultron to a worldwide audience. The film is predicted to be the biggest film of the summer and is set to eclipse the first film’s $1.5bn gross.

Marvel has yet to respond but sources claim they have “shrugged off” a cease-and-desist letter.