Taoiseach Leo Varadkar was branded an "airhead" and an "EU Toady" on the front page of the UK tabloid the Sun on Friday morning.
The insults are a response to Mr Varadkar's comments about the impact of a potential "no-deal" Brexit on air travel next year.
"The situation at the moment is that the United Kingdom is part of the single European sky, and if they leave the EU they are not, and that does mean that if there was a no-deal, hard Brexit next March the planes would not fly and Britain would be an island in many ways and that is something that they need to think about," the Taoiseach said in Kerry two days ago.
“You cannot have your cake and eat it. You can’t take back your waters and then expect to use other people’s sky.”
The UK tabloid, which has a circulation of 1.6 million, chose to interpret this as Mr Varadkar threatening to ban air travel in revenge for British Prime Minister Theresa May stopping Irish fisherman accessing UK waters.
It quotes the vocal pro-Brexit conservative MP Jacob Rees-Mogg as saying: “His words are those of an airhead.”
The headline does not appear in the Irish edition of the paper which, although owned by the same organisation, has its own newsroom based in Dublin.
An article on the Irish Sun's website takes a more sober tone. "Taoiseach warns a hard Brexit may mean planes leaving the UK may not be allowed to fly over Ireland airspace", the headline reads.
An editorial inside the UK version of the paper also calls the Taoiseach “a fool” and “a bigmouth” and said his “latest tantrum exposes Brussels’ intentions to keep us in its grip.”
It continues: “Imagine the cataclysmic self-harm of Ireland preventing planes from its biggest trading partner flying over it. And the impossibility of its own airlines avoiding UK airspace. It won’t happen.
"Varadkar must believe that these grenades he brainlessly lobs into the Brexit negotiations help Brussels. He is not bright enough to realise how absurd and unstatesmanlike he looks."
The Sun, which is owned by Rupert Murdoch, has been one of the most pro-Brexit newspapers since the UK voted to leave the European Union in June 2016. It has previously attacked the Taoiseach and other Irish politicians over what it sees as their intransigence on Brexit negotiations. Previous editorials have called Mr Varadkar "gobby" and told him "shut your gob and grow up".
