Well, seeing as how my own relatives from South Carolina would occasionally call our section of the family the "Damn Yankees"--I had heard it looooooong before I came to the UK. Honestly, the word doesn't bother me at all, but occasionally the tone of voice will make me raise my eyebrow. Usually it's someone's lame attempt at banter and not worth engaging with.
At least in my circle of UK friends, it is not automatically derogatory, but it is not as common as it used to be, maybe?