The creators of Captain Marvel was sued by DC Comics for "copying" Superman. So, in Britain, Mick Anglo created a rip-off called Marvelman. Marvelman was cut and paste Captain Marvel. Micky Morgan gained the power to become Marvelman (who had Captain Marvel-like powers) by saying "Kimota" ("Atomik" backwards) from an astrophysicist. He has two sidekicks: Dicky Dauntless aka Young Marvel and Jonny Bates aka Kid Marvelman (rip offs of Captain Marvel Jr. and Mary Marvel). They had bland adventures until they were canceled in February 1963.
Marvelman became a strip for Warrior. Alan Moore wrote Marvelman, which was the first superhero he wrote, with darker themes. An adult Micheal Morgan was a reporter who couldn't remember his adventures as Marvelman until he accidentally saw the word "atomic" backwards and spoke it aloud. Uttering the word (which is pronounced like "Kimota") turned him into Marvelman. He regained his memories but no one remembered Marvelman except as a comic books character. He battled against a power-mad Kid Marvel, resulting his in Kid's innocent alter ego going insane with guilt. Marvelman managed to muscle his way into a secret bunker, where he discovered the truth: he was part of "Project Zarathustra", where the government tested alien tech on human resulting in them gaining superpowers. Said humans were unconscious and had their mind fed comic book adventures as memories. On their "last " mission, the government tried to blow them with a nuclear weapon because the project was terminated. Marvelman turned to normal and lost his memories, but Young Marvelman was killed. Marvelman discovered his wife was going have a child who could become the first naturally born superhuman. Warrior stopped at issue 21. Due to pressure from Marvel Comics, the hero's name was changed to "Miracleman". He got his own series that lasted for 16 issues. Two alien races called the Warpsmiths and the Qys come to Earth. We discovered there are other native superhumans on Earth. The aliens, Miracleman, the brand new Miraclewoman and their allies have a gory battle with a now insane Kid Miracleman (Kid Marvelman). The battle kills 40,000 people and ends with Miracleman killing KM in his non-power form to prevent him from going on another ramage. In the last issue, the superhumans took over the world and were worshiped as gods. This series is characterized by extreme violent and gore that was to such a degree that was never seen before.
Neil Gaiman took over the series at issue 17. He plotted the series to have three books: "The Golden Age", "The Silver Age" and "The Dark Age". In "Golden Age", Miracleman and superhumans make the world a utopia via alien tech. Although, Miracleman questioned they are doing the right thing. This volume focuses the people affected by these event a la The Sandman. Neil Gaiman finished the first two issues of "The Silver Age", but didn't actually finish it. In the issues he did finish, Kid Miracleman was brought back...again.
Marvel Comic has gained the rights to the character. They plan to reprint various stories. They are trying to sort out some the copyright debates.
My main source was Wikipedia.