As other people have pointed out, in the United States, GW's trademark for "Space Marines" does not include fiction in their "realms of business." So this is ex

As other people have pointed out, in the United States, GW's trademark for "Space Marines" does not include fiction in their "realms of business." So this is extremely dubious on its face. Furthermore, under UK law, a trademark can be invalidated on "absolute grounds" which "cover defects in the trade mark itself": The most common absolute ground for invalidation is that the trade mark is descriptive of the registered goods and/or services, or that it is generic for those goods/services, or otherwise non-distinctive and should therefore be free for everyone to use. http://www.ipo.gov.uk/invalidtm.pdf http://www.ipo.gov.uk/invalidtm.pdf And, actually, according to that law, anyone can apply to have the mark declared invalid on absolute grounds. The underlying issue at hand -- and this applies to American law as well -- isn't precisely about "prior art." It's about whether the phrase "space marine" is already too generic for the trademark to hold, especially when applied to fiction. "Marine" certainly isn't a GW trademark; this whole claim is predicated on the notion that it becomes uniquely theirs when the word "space" is put in front of it. ...so the linked post was infringing. Sorry, but it was. That's not the question, is it? The question is whether it should be infringing.