Corruption was a distinctively legal phenomenon in eighteenth-century Britain, because government was defined by written and unwritten law enforced by and though the Court of the Exchequer.  Drawing on JGA Pocock’s concept of the ‘ancient constitution’, this paper will argue that the ‘ancient course of the Exchequer’ essentially forced public officials to be corrupt, as embedded popular and legal attitudes and precedents clashed with new forms of government, administration and finance.