Green’s Dictionary of Slang

(UK Und.) to pick a pocket by turning it inside out.

1821		D. Haggart Autobiog. 12: The keek cloy is easily picked. If the notes are in the long fold, just tip them the forks; but if there is a purse or open money in the case, you must link it. [Ibid.] 172: Link to turn out a pocket.
1835		G. Kent Modern Flash Dict.
1848		Flash Dict. in Sinks of London Laid Open.