Do me a lemon!

Do me a lemon!

You must be joking; I can't believe this; that's nonsense. A slang phrase specific to London, England. Do me a lemon, man! No way I'm paying for tap water. You're going to fine me for spitting on the footpath? Do me a lemon!
Farlex Dictionary of Idioms.
See also:
  • garbage
  • iron poof
  • bone
  • bones
  • flash
  • flash on
  • flashing
  • blimp
  • blimp out
  • gun