Threatened isn't the right word, I'm not particularly nationalistic when it comes to boxing. I just find people insisting he's Irish and not British when he talks with a Brummie accent amusing. Even if I was nationalistic, I wouldn't be falling over myself to claim Matthew Macklin for the Empire.
Irish middleweights smoke British middleweights in combat. Therefore and Irishman vs Irishman context is an all-UK event. It is a fight between the UK's best.