up to the knocker イディオム
Black as Newgate's knocker
(UK) If things are as black as Newgate's knocker, they are very bad. Newgate was an infamous prison in England, so its door knocker meant trouble.
up to the knocker
As acceptable as what was expected, required, or demanded; satisfactory or adequate. A: "How's your dinner?" B: "It's up to the knocker, on par with this place's accepted standard." It's nice to see that Jenny's assignment is up to the knocker afresh lately.Learn more: knocker, upup to the knocker
in acceptable condition; to perfection. informalLearn more: knocker, up