The breakfast time radio host sparked controversy last November when she said on air that the Britain's Got Talent star was "not right in the head".

The remarks to her co-presenter Ivan Yates and Newstalk stable-mate Tom Dunne sparked an investigation by the Broadcasting Authority of Ireland (BAI).

The watchdog upheld a complaint by a member of the public in a ruling that attacked the comments as inherently offensive, disrespectful and not editorially justified.

The BAI rejected claims by Newstalk bosses that Ms Byrne was referring to the hit television talent show rather than the Scottish winner, who has become a global phenomenon.

It said the language used and manner of presentation was not appropriate, as the station's breakfast show was meant to be a factually accurate news and current affairs programme.

The watchdog also hit out at both Mr Yates, a former Government minister, and singer-turned-disc jockey Mr Dunne for failing to intervene to moderate the comments.

Among the offending remarks by Ms Byrne, listed by the BAI, were: "She annoys me. I can't listen to her or watch her. She does my head in."; "The whole thing, she's a freak show, she is a freak."; "But she's not right in the head."; and "Her voice isn't brilliant, it's because she's a freak that she's up there."

The BAI said the comments were likely to cause offence.