Green’s Dictionary of Slang

1. (Aus.) a prison.

1847		A. Marjoribanks Travels in New South Wales 225: There is a large penitentiary erected for the female convicts, called the female factory at Parramatta.
1860		Cornwall Chron. (Launceston, Tas.) 18 Aug. 5/4: Her majesty’s Female Factory in Hobart, where events befal of the most tragic and appalling nature.

2. (UK Und.) a police station, esp. a large, Victorian-era station in the London Metropolitan area.

1891		F.W. Carew Autobiog. of a Gipsey 426: A stranger of foreign aspect whom a plain-clothes D. from ‘the Factory’ would most assuredly have catalogued as ‘suspicious’.
1938		F.D. Sharpe Sharpe of the Flying Squad 330: factory (the) : The police-station.
1955		B. Hill Boss of Britain’s Underworld 55: Down at the factory the Commissioner of police was going mad.
1974		G.F. Newman You Flash Bastard 25: Although Sneed and DC Gordon had both started in CID together, the latter having followed him to Divisional HQ from their previous factory, that was the only parallel in their careers.
1984		‘Derek Raymond’ He Died with His Eyes Open 12: You’d better call the Factory and I’ll have his property sent over.
1989		J. Morton Lowspeak.