Detonator X is a comic strip by Ian Edginton and Steve Yeowell published in 2000 AD progs 1534 to 1543 (pictured). Karl Richardson produced a Detonator X cover for prog 1534, which contained the double-length opening episode.
In the extended edition of Thrill-Power Overload, Edginton says, "I'd never done big robots fighting giant monsters, basically, and it was on my bucket list. It was a movie-of-the-week formula with no intelligent design behind it and it came out before Pacific Rim, so I guess it rode the zeitgeist. Who doesn't love giant robots?"