If Ireland win in Paris, they’ll be champions I reckon a_a – it would be difficult for either Wales or England to rack up the points needed in the remaining games. England and Wales will win their last games. If England were to trounce Wales this afternoon, then they have a chance to make up the points but are away against Italy.
So the winners of today’s game will most likely finish with 4 out of five wins. Ireland will lose in France anyway, so it’s today’s winners that will take the championship.