"The rule against duplicitous counts in an indictment originated as early as the seventeenth century. See, e.g., Smith v. Mall [1676] EngR 492; (1623) 2 Rolle 263 [81 ER 788]; R. v. Stocker (1696) 5 Mod 137 [87 ER 568]. It may be, as suggested by Salhany in "Duplicity - Is the Rule Still Necessary?", (1963) 6 Criminal Law Quarterly, vol.6 (1993) 205, at pp. 206-207, that the rule grew out of the strict formalities associated with criminal pleadings at a time when the difference between misdemeanour and felony was the difference between life and death. However, the rule against duplicitous counts has, for a very long time, rested on other considerations. One important consideration is the orderly administration of criminal justice. There are a number of aspects to this consideration: a court must know what charge it is entertaining in order to ensure that evidence is properly admitted, and in order to instruct the jury properly as to the law to be applied; in the event of conviction, a court must know the offence for which the defendant is to be punished; and the record must show of what offence a person has been acquitted or convicted in order for that person to avail himself or herself, if the need should arise, of a plea of autrefois acquit or autrefois convict. See, generally, R. v. Sadler (1787) 2 Chit 519; R. v. Hollond [1794] EngR 2213; (1794) 5 TR 607, at p. 623 [1794] EngR 2213; [101 ER 340, at p.348], per Lord Kenyon C.J. at p 623 (p 348 of ER). See, as to the need for distinct consideration in relation to penalty, R. v. Stocker; R. v. Sadler; R. v. Morley [1827] EngR 282; (1827) 1 Y. & J. 221 [148 ER 653]; Cotterill v. Lempriere (1890) 24 QBD 634, per Lord Coleridge C.J. See, as to the availability of a plea in bar, R. v. Robe (1735) 2 Str 999 [93 ER 993]; Davy v. Baker [1769] EngR 69; (1769) 4 Burr 2471 [98 ER 295]; R. v. Wells; Ex parte Clifford (1904) 91 LT 98; R. v. Surrey Justices; Ex parte Witherick (1932) 1 KB 450.
The rule against duplicitous counts has also long rested upon a basic
consideration of fairness, namely, that an accused should know what case he or she has to meet. See, for example, R. v. Robe, at p 999 (p 994 of ER) where it was said "this is so general a charge, that it is impossible any man can prepare to defend himself on this prosecution ... ". See also R. v. Hollond, per Lord Kenyon C.J. at p 623 (p 348 of ER); R. v. North (1825) 6 Dowl & Ry 143, at p 146 (28 RR 538, at p 541); R. v. Morley, at pp 224-225 (p 654 of ER); and Cotterill v. Lempriere, per Lord Esher M.R. at p 639. Of course, the degree of unfairness or prejudice involved will vary from case to case, and it may be, as suggested by Professor Glanville Williams in "The Count System and the Duplicity Rule", [1966] Criminal Law Review 255, at p 264, that on occasions the uncertainty is not "such as to disable the defendant from meeting the charge".[14]