Green’s Dictionary of Slang

1. an after-hours or unlicensed drinking club.

1955		B. Hill Boss of Britain’s Underworld 124: The Stoprk Club was both a speiler [sic] and a drinker.
1970		G.F. Newman Sir, You Bastard 194: Some afternoons [...] were best spent in a drinker.
2004		(con. 1980s) N. ‘Razor’ Smith A Few Kind Words and a Loaded Gun 285: If you go mob-handed to an after-hours drinker and try your luck starting fights with strangers, how can you turn around and cry ‘copper’ when you come unstuck.
2014		T. Black Artefacts of the Dead [ebook] They’re going to check a few hacks’ drinkers.

2. a public house.

1979		A. Payne ‘The Dessert Song’ in Minder [TV script] 16: Terry down the drinker wrestling Irishmen?
1989		M. Amis London Fields 336: With a shudder, he’d rear up, fling on a mack and, Keith assumed, slope off down the drinker.
2009		T. Black Gutted 167: There was a nice-looking little drinker over the road, gas lamps hanging alongside the Younger’s Tartan Special gadgie.
2013		T. Black Ringer [ebook] n.p.: I [...] heads out for a pint down the drinker.