couldn't stop a pig in a passage

A Yorkshire idiom describing someone who is severely bow-legged — their legs so curved that even a pig could pass between them unchecked. Typically deployed in good-natured ribbing, it reflects the British tradition of mocking physical traits with elaborately specific rural imagery. The phrase is largely obsolete outside older Yorkshire dialect speakers; in active use it would function as a teasing put-down with a comedic country flavour.

(Yorkshire, idiomatic) To be bow-legged.