Throughout my lifetime there have been many times when I have been the target of abuse from English people firstly because I am from Ireland, and secondly because I am specifically from Northern Ireland (especially throughout the years of the "Troubles").
One memorable example occurred on a bus in Newcastle upon Tyne when a (drunk) woman, on hearing my accent, berated me personally for all the crimes, atrocities and misdeeds committed by Republican terrorists on the English mainland. The diatribe continued unabated all the way from Newcastle City centre to Ocean road in South Shields.
Although animosity by white English people toward white Irish people is not, strictly speaking, racism, the effect on the victim is the same - anger, embarrassment, bewilderment, resentment, and occasionally fear. That is exactly how I have felt each time it happened.
I have even been abused for being Irish by white English people visiting Ireland. Most visitors who come to our shores in Ireland seem to enjoy our hospitality, our friendliness, and the spectacular scenery of the island of Ireland, yet a small percentage feel it is acceptable to invoke negative stereotypes of Irish people, to express thinly veiled insults and downright verbal abuse aimed at the Irish inhabitants simply because they are Irish.
I have never received similar abuse from a Scottish or Welsh person. Possibly because they know what it feels like to be on the receiving end of such nationalistic abuse?