Who Could Be Called A Living Legend Of English Literature For Both America And England?

It might depend on your definition of literature. Stephen King is certainly a living legend worldwide, but not everyone would class his writng as "literature." The same probably goes for a lot of popular authors.

I find that US authors tend to be better known in Britain than the other way round. One author who has really iconic status on both sides of the Atlantic is Toni Morrison. Her novels, especially Beloved and The Bluest Eye, are studied in schools and colleges in both countries, as well as Canada; Beloved has now been filmed. Canadian Margaret Atwood is another possible "living legend" who works in the US and is hugely admired all over the English-speaking world (and outside it) The Handmaid's Tale especially has become part of the "canon" of literature.

It's harder to find a British author with high recognition and status in America; you could check out Martin Amis, author of Money and Time's Arrow among others. There is a website for him at www.martinamisweb.com