British “avowedly pro-EU politicians”
Not a meaningful disclaimer. Preface all of the EU politicians across all the member states with their country of birth and it will mean the same thing. By their allegiance to the EU, they have disavowed their identity as Britons.
Fabians (long affiliated with Britain’s Labour Party) are just as internationalist as Marxists; they only differ in terms of the matter of violent revolution versus gradual political alteration of the status quo—take note of how the EU operates in this fashion, and also take note of Tony Blair’s expressed desire of being the first “EU president” (the job went to Herman van Rompuy instead). It really ought to be self-explanatory. Fabians have migrated into the Tories as well; if the gay marriage bill was not demonstration enough of that, I don’t know what is.