An interesting response to this question from Hugo Brady:
"Orwell
disdained other British socialists who were 'too pure' to be patriots. Yet he
was in every sense a good 'European': he fought with the International Brigades
in the Spanish civil war, wanted to translate Émile Zola (J'accuse!) and hated passports and
border controls. In other words, he was ready to accept the complexities of
European inter-dependence and think outside of national boundaries when the
cause was right."
Read more here.