A traditional English breakfast just isn't the same without traditional British back bacon. Like the rest of the planet, the British love bacon, but only in Great Britain is bacon a centuries old tradition, the history of bacon involves ancient genetic pig bloodlines specific to a region, specific cuts of pork and traditional methods of smoking the bacon.
The term 'Back Bacon' refers to a very specific cut of bacon and only vaguely to the part of the pig the pork is cut from, which is not at helpful if you need to know exactly how to cut traditional British Back Bacon.