In Victoria, the rule against duplicity is a common law rule concerning the way criminal charges are drafted. The rule provides that the prosecution must not allege the commission of two or more offences in a single charge in a charge-sheet. Such a charge is sometimes said to be 'duplex' or 'duplicitous'.
While the rule is well established in criminal law, prosecuting agencies sometimes find it difficult to apply in practice. It is often stated that there is no 'technical verbal formula of precise application' that provides an easy guide to applying the rule.
However, like other common law and statutory rules  for drafting criminal charges, the rule stems from two important principles:
- First, as a matter of fairness, a person charged with a criminal offence is entitled to know the crime that they are alleged to have committed, so they can either prepare and present a defence or decide to plead guilty.
- Second, the court hearing the charge must also know what is alleged so that it can determine the admissibility of evidence, focus on the relevant fact-finding task, consider any possible defences which might be available, and determine the appropriate punishment in the event of a conviction.
When does a charge contravene the rule against duplicity?
There are generally considered to be two ways in which a charge might offend the rule against duplicity: These are:
Patent duplicity, where a single charge alleges the commission of two separate offences.
Latent duplicity (also called 'latent ambiguity' or 'latent uncertainty'), where a single charge alleges the commission of only one offence, but the evidence led by the prosecution in relation to the charge discloses a number of separate offences, all of which could fit the allegation described in the charge.
In either case, the accused may be prejudiced in a number of ways by a duplex charge. A concise summary of the prejudice that may flow in such cases can be found here in the judgement of Redlich JA in the Victorian Court of Appeal decision of PPP v The Queen.
An excellent summary of the history and development of the rule can be found in the judgement of Leeming JA in the NSW Court of Criminal Appeals' decision of Environment Protection Authority v Truegain Pty Ltd.
Distinction between a duplex charge and a charge alleging an offence 'in the alternative'
Sometimes a statutory provision will state that an offence can be committed in alternative ways (for example, intentionally or recklessly causing injury). Under the Criminal Procedure Act 2009 (Vic), the prosecution may generally plead that an offence was committed 'in the alternative' in the one charge.
However, it can sometimes be difficult to apply this exception in practice. One problem is that a single statutory provision sometimes creates separate offences. Whether a statutory provision creates separate offences or a single offence that can be committed in alternative ways can only be identified by process of statutory interpretation. VGSO's lawyers are experts in statutory interpretation and are pleased to provide assistance in this regard.
Exception for offences that are part of a 'single transaction' or are 'continuing offences'
An exception to the rule against duplicity is where an accused is alleged to have engaged in a course of conduct consisting of a series of acts, each which might constitute a separate offence, but which are so closely related that they can be considered one act or a 'single transaction'.
Whether such allegations are considered a 'single transaction' depends on the period of time over which the acts occurred, the similarity of the acts, the physical proximity of the place where the acts happened, and the intention of the accused throughout those acts. However, even where such a connection exists, it may still be necessary to charge one or more of the acts separately. For example, an accused might have a specific defence to one or more of the alleged acts, or the evidence available to prove some acts may be substantially weaker than for others. Fairness dictates that these acts are set out in separate charges.
There are also offences which require proof of a number of acts in order to establish an offence, even where the individual acts may themselves constitute distinct offences. These are sometimes called 'continuing offences'. Examples include allegations of stalking or persistent sexual abuse of a child.
Exception for 'rolled-up' charges
Another important exception to this rule applies where an accused waives the right to object to a charge that is affected by duplicity by pleading guilty to a 'rolled-up' charge.
A rolled-up charge can comprise a number of separate offences against the same statutory provision, even where they do not amount to a 'single transaction' (eg where the acts occurred on different occasions). This is usually done in negotiating a plea of guilty to create an administrative convenience rather than to reduce the culpability of the accused.
It is important for prosecutors to ensure that the summary of facts presented to the Court at sentencing explains that a rolled-up charge encompasses a number of distinct offences, so that the accused is sentenced accordingly.
Overcoming duplicity in a charge
Duplex charges are not automatically struck out by a court. Instead, the court will usually require the prosecution to 'elect' which of the separate offences it wishes to proceed with (where there is patent duplicity) or to provide sufficient particulars of the charge to identify the precise instance of offending (where there is latent duplicity). If the prosecution fails to make an election or identify the precise instance of offending, the Court may act to strike out or 'stay' the charge.
Whatever the case, it is always important that proper particulars are given, so that the accused knows all of the relevant facts, matters and circumstances alleged against them. A failure to provide such particulars can still result in a charge being struck out.
If you require advice or assistance in drafting charges or criminal prosecutions generally, contact:
 The rule applies equally to the drafting of counts in an indictment, where a matter is prosecuted by the Director of Public Prosecutions in the County Court or Supreme Court.
 Stanton v Abernathy (No 2) (1990) 19 NSWLR 656 at 666 per Gleeson CJ.
 See Schedule 1 of the Criminal Procedure Act 2009 (Vic).
  VSCA 110 at para .
  NSWCCA 204 at paras  to .
 Clause 3(3) of Schedule 1 to the CP Act.
 For example, section 52 of the Summary Offences Act 1966 (Vic) provides: "Any person who assaults resists obstructs hinders or delays … any member of the police force or a protective services officer in the execution of his duty under this Act or otherwise… shall be guilty of an offence". This provision arguably creates a number of distinct offences, rather than a single offence which can be committed in different ways.
 Such conduct is sometimes referred to as a 'composite activity'.
 Walsh v Tattersall (1996) 188 CLR 77 per Kirby J; R v Khouzame & Saliba  NSWCCA 173; (1999) 108 A Crim R 170; R v Heaney  VSCA 74; Rixon v Thompson  VSCA 84. It is useful to look at cases of the higher courts to get a flavour for what fits within this exception. The decision of Ashley JA in R v Heaney and the decision of the Court of Appeal in Rixon v Thompson are good starting points.
 See: Rixon v Thompson  VSCA 84 per Maxwell P, Weinberg JA and Kyrou AJA at paras -, -.
 Section 21A of the Crimes Act 1958. Section 47A of the Crimes Act 1958.