Conall Ó Máirtín is a BBC Gaeilge reporter from County Tyrone whom I first saw in this interesting episode https://www.youtube.com/watch?v=KcuxN8_dbks. While he does advanced narration in Irish and seems to have great fluency, his phonology is highly anglicised just as for many other speakers.

Just curious: is he a native speaker, or "just" a highly proficient L2 speaker? Even most Gaelgeoirí from the Gaeltacht I've heard have more or less anglicised pronunciation (at least the "r" and "l") - even people like Liadh Ní Riada who says she only knew Irish until starting school and to this day is more comfortable with Irish than English. FWIW contact with English did the same to the Pennsylvania German language.

Well that is a long way from being the worst accent in Irish. It is not actually a bad accent at all. As a Tyrone man, he can't be a true native speaker, although some people in NI do claim to be neo-natives - and nearly all of them speak with much heavier accents than this man. Liadh Ní Riada - I've just watched a video of her speaking Irish on Youtube, and she is also a very good speaker. I'm not sure what you're defining as "anglicised pronunciation".

I never know what "accent" means to English speakers, for some, it's a synonym of "dialect", for others, it refers to the pronunciation in general, and for others, it has the meaning of "prosody" (melody of speech)...

I've just watched the beginning of the video; his prosody isn't bad but he makes several pronunciation mistakes as most non-native speakers do: pronouncing r as in English, pronouncing ch like k quite often, pronouncing slender ch either as broad ch or k. Also he sometimes replaces /h/ by the sound of broad ch...

To me his pronunciation is very different from that of the native speakers you can hear in the video...

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