In the United States, you will get fat-streaked bacon, which comes from the belly. In the UK, bacon is more rounded and leaner and comes from the back of the pig.
You can find pork belly bacon in the UK, but it isn’t a breakfast staple. Pork belly bacon is often reserved for hors d’oeuvres and other dishes that use the meat as a highlight.
UK-style bacon can be found in the U.S., but it won’t be under the bacon label because only bacon produced from the belly of the pig can be labeled as such in America.