go down the pan

To fail or be completely and irreversibly squandered, lost, or destroyed. Primarily heard in UK. In an instant, we saw all our hopes for our business go down the pan. All those years of research went down the pan when they pulled our funding. My father's company is now going down the pan because of the incompetent new CEO.

go down the pan

reach a stage of abject failure or uselessness.

1997 Ian Rankin Black & Blue My company's just about given up trying to sell to the oil industry. They'd rather buy Yank or Scandinavian…no wonder Scotland's down the pan.

go down the ˈpan

(British English, slang) be wasted or spoiled: That’s another brilliant idea down the pan.

Pan is an informal word for the bowl of a toilet.