If you are a sensible, upstanding, responsible sort of bloke with no history of prattship the beak may just belive you or at least give you the benefit of the doubt
Oh, wait!
If it's true that he didn't intentionally drink alcohol then I would have thought he would have an ideal defence against the drink driving charge, assuming he could persuade the magistrates that it was true.
Or maybe, just maybe, it's not true ??? Surely he's not being economical with the...