Comic book v. graphic novel tags

Today's Guardian reports Bobby Joseph being appointed the UK's next comics laureate. Congratulations.

Him being described as "comic book author and graphic novelist" had me checking my tags, and realising I don't really understand the difference between the two, if it's really a difference.

Are V for vendetta and Gemma Bovery graphic novels because they are complete stories, and if so is the same true of the Asterix and Tintin volumes?

Are the likes of Mrs. Weber's diary, If..., Calvin and Hobbes, The Cloggies, Questionable content, collected newspaper, magazine and web-based comic strips, with overarching stories linking blocks of strips, also graphic novels?

While presumably the likes of Andy Capp of The Daily Mirror, London, Dilbert and Alex anthologies, one story per strip, are comic books?

Or have I got the wrong end of the stick?

I'm not sure there are any satisfactory definitions. If we go by the criterion of "completeness", then clearly there are a gajillion precedents that fit that criterion but that people don't, or at least didn't think of as "graphic novels"--hundreds upon hundreds (thousands?) of francophone, Italian, Latin American titles. I've seen attempts to define it as something oriented to adults, but then so are the many sexy comics. Does Milo Manara now draw graphic "novels"? Eh...

On the issue of news press comics, or true "strip" comics, it at least seems easy to say that gag comics aren't "graphic novels" even when published in anthologies. But there were other, serialised comic strips that told a complete story in installments. Flash Gordon, Rip Kirby, Terry and the pirates etc. Back to the original question...

Graphic novel is a marketing term for people who are afraid to admit they read comics.

I have increasingly in the library world seen "graphic novel" used specifically for comics that were not originally published serially or in anthologies - it's a graphic novel if it was only ever intended to be sold in a single bound trade volume as a single complete book. So, say, Manara's works that were originally published in magazines aren't graphic novels, even if there were later collections, but some of his that were published originally in book form would be.

But mostly it's still what >3 Crypto-Willobie: said.