put the tin lid on something
put the tin lid on (something)
To finish or complete a bad experience or situation in an especially negative way. Primarily heard in UK. The downgrading of the company's credit rating puts the tin lid on a disastrous year for their financial situation. What a bad day: I left my phone in the grocery store, my car broke down on the way home, and, to put the tin lid on it, my groceries broke through the bag as I was walking to the front door.
put the tin lid on somethingBRITISH, OLD-FASHIONED
You say that something puts the tin lid on a bad situation when it is a final unpleasant event in a series. Next day, to put the tin lid on things, a hospital appointment letter for Jane arrived from the clinic.