Green’s Dictionary of Slang

a beating, often in the context of a punishment.

1589		Hay any Work for Cooper (1845) Aiij: By the swoorde I threatned him with blowes, and to deale by stafford law .
1599		N. Breton ‘The Scholler and Souldier’ Wil of Wit in Grosart (1879) 29/1: Among souldiers, Stafford law, martiall law, killing or hanging, is soon learned.
1647		M. Corbet A Learned and Eloquent Speech in Harleian Misc. I (1808) 273: We have unlawfully erected marshall law, club law, Stafford law, and such lawless laws as make most for treason.