Personal view.
Anyone of any nationality, colour, race, religion or creed, born or living in the British Isles can say they are :-
British, English, Scotish, Irish or Welsh. Their choice.
If people prefer, they can state they are some other nationality to which they hold their allegiance, whats wrong with that?
I personally choose to say I am English, although my blood-line from my parents sides are French & Jewish.
My main point is, that not many people in the UK can claim "pure" ancestry (whatever that is) so the whole argument is clearly stupid, so get over yourselves eh?
The rioters / lawbreakers / thieving / violent / morons that have seized so much news & Forum space dont deserve it, and are spread across a broad age range & are from many different social groups.
All are as guilty as each other of crimes against the SOCIETY we all live in!