American. I normally drink my tea black, but milk is nice with earl grey on occasion.
And typically, the milk isn't hot. You pour it in already steeped tea, like you would if you drank coffee with cream.
That said, I do occasionally steep my earl grey entirely in steamed milk and add a little vanilla and it's just a nice treat. But I'm not looking for a bitter flavor at that point either.
Honestly, I thought putting milk & sugar in your tea was bonkers until I tried it from my British friends. It works with traditional English teas, but not really with American/orange pekoe teas.
There are some English teas that are so bitter that they need sugar in order to be palatable.