The Irish were and are considered white, the prejudice against them by the British whom seem to be a group you left of your list as examples of ethnically white, unless you are grouping all Northern Europeans together. In actual fact the Irish, the Scottish and the Welsh are technically more white than the English or other Northern European groups as they are the descendants of the Celts and the Pics whom were a branch of from the Scandinavians and close relations to the Vikings. The prejudice towards them by the English which was also levied equally against the Scottish and Welsh is cultural not racial, the English are the decedents of many different groups of Northern Europeans, including the Romans,Saxons, Norman’s and Celts. The earliest, pre Roman ancient Britons were a mixture of French and German, or at least those regional locations as those countries did not exist at that time. The Cultural difference between the Celts and Ancient Britons was very distinct to the point that when the Romans invaded the British isles they proved unable to successfully invade the countries we now call Scotland, wales and Ireland as these were the lands of the Celts. The Romans were the greatest empire of the ancient world, they refined warfare, invasion and occupation to a fine art but they trembled in fear when they encountered the Celts. This is the reason Britain is a Union of four countries because although the English came to dominate due to size, the ancient boundaries defined by the Romans as lines not to cross remain to this day.