Popeye and Inspector Gadget were Americans, so they are ruled out
The reason Asterix is good is that as well as being witty and exciting, he was also incredibly French, you could not mistake him for another coutnry at all, he never gets the girl, and he is fighting a hopeless battle which he won't win, but he has superpowers which means he will never lose either, just carry on fighting his battle
he's as french as Marianne running about with her tits oot
Dangermouse is just as English because he is an altogether shady character, he's an obvious pisstake of James Bond, he goes on adventures all over the globe, and gets into increasingly surreal situations. He recognises the surrealism of the situation, but being English he just pretend that nothing has happened. He even has a friend from a lower class than him to patronise. He is also a miserable sarcastic cunt