One may swallow this lie
I believe the answer is:
pork pie
I believe this clue is a double definition.
'one may swallow this' is the first definition.
(type of food)
'lie' is the second definition.
(pork pie is Cockney rhyming slang for lie)
(Other definitions for pork pie that I've seen before include "swallowed by gull" , "Flat-crowned hat" , "One going to the head" , "Story" , "A fib, some say" .)