A friend I spoke to who is a little older and had grown up in the UK spoke about being unable to think of himself as 'white' because he was Irish in England in the 1970s -- and while he may have white skin, the English are masters at picking up nuances of accent, and his name is Pat, so he could conceal his ethnicity only for a few seconds on meeting, and experienced active discrimination. So, while he knows that he is considered 'white' now, his childhood experiences still leave him feeling otherwise.

And there are plenty of other meaningful divisions of whiteness. Being Catholic was a real social divider in Australia and the US as late as the 1950s, and still is in some parts of the UK and Ireland, for example.

Whiteness is a complicated thing. I've recently had the weird experience in Alice Springs were people would often lapse into talking about the 'black' and by contrast 'white' populations of the town (and I've been guilty of it myself), when what they really meant were the Aboriginal and non-Aboriginal parts of town (black Americans were definitely part of the 'white' community, as were, say, hospital staff of south east asian decent etc).