(noun) A Police Officer (Brit., vulg.)
Derived from the well-known British spoonerism, "I haven't had a cunt
all night, drinkstable!" (an inebriated corruption of "I haven't had a drink all night, constable!" - commonly offered in one's own defence when apprehended by the forces of law and order for some minor motoring infraction - eg., running down a Sunday school outing or driving one's Bentley through the Food Hall at Harrods).
Banned for six months? Come off it, drinkstable - I've only had a dozen pink gins, a jug of Pimm's, three halves of light ale and a schooner of amontillado. My cousin's a JP, you know!