"Nobody has yet convinced me that there is one "correct" definition of Britishness"

It is difficult but I think the only place where you really would have to walk on egg shells a bit with this is parts of Northern Ireland. It can be a serious issue over there. You wouldn't get the really serious anti-British attitudes anywhere in Great Britian that you may get from sections of the nationalist community but neither would you get the overt Britishness that you find in the unionist community either.

Indeed the Institute for Public Policy Research in their last study on the subject found that only around 10% of people in England regarded themselves as principally or only British rather than English. The figures in Scotland tend to be slightly less only about 8% or so regard themsleves as principally or only British. They come to the conclusion that nowhere in Great Britian is there a significant section of the population who's principle identity is British. That though does exist in Northern Ireland. I can understand how it is confusing for people