drive a coach and horses through

drive a coach and horses through (something)

To expose the flaws in something, such as a statement, argument, or belief. The suspect had said he wasn't there that night but then drove a coach and horses through that idea with today's contradictory statement.
See also: and, coach, drive, horse, through

drive a coach and horses through something

Fig. to expose weak points or "holes" in an argument, alibi, or criminal case by [figuratively] driving a horse and carriage through them. (Formal. Emphasizes the large size of the holes or gaps in the argument.) The barrister drove a horse and carnage through the witness's testimony. The opposition will drive a coach and horses through the wording of that government bill.
See also: and, coach, drive, horse, through