William Caxton set up England's first printing press at Westminster in 1476. His press introduced the technology of movable-type printing to England and helped transform the production of English books.
Caxton had learned about printing on the Continent. Before returning to England, he operated a press in Bruges, where he printed Recuyell of the Historyes of Troye, the first book printed in English. At Westminster, his early publications included works associated with Geoffrey Chaucer, including The Canterbury Tales.
The date 1476 is sometimes confused with 1450, the approximate period when Gutenberg's printing revolution began in Mainz, or with 1473, when Caxton printed in Bruges. The question asks specifically about the first press established in England, making 1476 the accepted answer. Caxton also influenced English language standardization by choosing and repeatedly printing forms of the London dialect.