Of British origin, this style is now popular worldwide and the use of local ingredients, or imported, produces variances in character from region to region. Generally, expect a good balance of malt and hops. Fruity esters and diacetyl can vary from none to moderate, and bitterness can range from lightly floral to pungent.
American versions tend to be cleaner and hoppier, while British tend to be more malty, buttery, aromatic and balanced. (BeerAdvocate)