All my eye and betty martin

In Britain during the 1700s, the phrase was a common claim of dismissal (similar to 'nonsense', or 'hogwash'), or a way to declare disbelief of an absurdity. It possibly originated as the punch line of a joke (though this is likely a folk etymology). Most variations of the joke involve a British sailor visiting Italy. He overhears a Latin prayer, "Ah! [Da] mihi, beate Martine" (which translates to "Ah! Grant to me, blessed Martin", referring to St. Martin). The sailor mishears the prayer, and later uses the phrase as "All my eye and Betty Martin".