'Bap' is northern, also 'barm'..you also hear 'butty' (more in the south). I think I've heard 'cob' as well somewhere. As ewie says, you usually need to specify a filling, otherwise it's just a breadcake. Oh! There's another one.What are British English synonyms of "roll", "sandwich"?
I had the vague recollection that one term was "bab", but I might just be confusing that with "bun". Total confusion is not unknown to my mind.
I can confirm with some certainty that in the north of England at least 'butties' are not just bread and butter, but whole sandwiches. 'I've got some butties' = I've brought a packed lunchA butty is, surely, some kind of bread with butter and a filling?
butty A slice of bread and butter.
Definitions are from the OED.