If someone is As Drunk As A Newt they are pretty drunk. Apparently, during the 17th and 18th centuries "newts" was the nickname that gentlemen gave the boys who looked after their horses while they went out on the town for the night. As they spent their evenings in pubs and opium dens they'd often send out "warm-up" drinks to the newts who, by the end of the night, would usually be rolling drunk.