The Official Online RBS 6 Nations Store is open. The store has everything you need to get behind your team during the RBS 6 Nations, plus the store is now fully stocked with a much wider range of rugby merchandise.
And that dominance is unquestioned as Ireland have prevailed in seven of the last eight RBS 6 Nations clashes between the two sides, including on three of their last four visits to Twickenham.
And O’Callaghan, who admits spending time with English players on Lions tours has changed his perceptions, revealed the sight of the Red Rose shirt pushes all of Ireland’s buttons.
"I wouldn't say I'm friendly with any of their players, but I've been on Lions tours with them," he said. "The biggest thing I've taken away those tours is that you can build up a perception of people before you actually get to know to them.
“I remember going on Lions tours believing half these guys are idiots and that I wouldn't like them, only to come away thinking they're the soundest guys you could meet.
“But come Saturday they'll be in an England shirt and nothing will change in the way we treat them.
“England shirts are a red rag to the Irish. When we play England in anything, we want to do well and perform. Maybe it goes back to Euro 88 [the Republic of Ireland beat England 1-0] or something like that – you tend to remember great days of Irish results against England teams.”