Actually, the Brits should have handed all their lands and stuff over to the Irish, as the Brits were able to run around the planet and subdue all sorts of other peoples, but they never quite managed to do so with some folks just a short sail away to their west.
So it is obvious the Irish were stronger than the Brits and so the Brits should have handed over all that stuff to the Irish. The Brits would have been perfectly safe, as the Irish weren't the least bit interested in trying to take over the pitiful islands to their east; the many little ones and that big one.
Anyway, the Irish would have kept the Brits happily employed building those neat sailing ships and crewing them under Irish guidance.
Just imagine, in North America, India, and other areas we'd all be speaking/reading/writing Irish now, instead of that weird English language. Of course, that would also mean that even to this day all those areas would be under good Irish control and a happy world it would be. Putin could never have been able to handle an Irish Empire. In fact, I think mainland China would have been completely taken over by the Irish.
Upon deeper consideration, I think by now this would be called Irish Earth. All the planet would be speaking Irish and we'd all be so happy together. Maybe even those two world wars wouldn't have happened. Nobody could defy the Irish will.