****As late as the 1950s researchers were busy collecting data among Irish people such as hair colour and height, in order to categorise them as a ‘race’ and define them as different to the British.*****
‘British’ is not a ‘race’ - it is a nationality or descriptive of territory. Should have used - Anglo-Saxon.
“British” isn’t necessarily a reference to English. Even the Celts in the British Isles used that term before the English arrived.