Green’s Dictionary of Slang

anything obtained for free, esp. as a bribe given to a corrupt police officer.

1921		N&Q 12 Ser. IX 346: Freemans. Free; received by gift or otherwise acquired.
1922		‘J.H. Ross’ Mint (1955) 38: Sort of thing the civvies in London pay fifty quid for, we get harry-freeman’s.
1945		D. Bolster Roll On My Twelve 134: Harry Freeman’s ... gratis, free of charge.
1995		J. Cameron Vinnie Got Blown Away 7: [of a detective] Short, fat and liked freeman’s. [Ibid.] 30: Ricky was always fucking off somewhere on freeman’s.
2002		J. Cameron Hell on Hoe Street 28: ‘No such thing as a free ride Nicky innit?’ ‘Straight up. Freeman’s catalogue. Like a holiday.’ [...] 191: Half the security was ex-cons anyhow so you only had to tip them a freeman’s and you walked.