The offence of criminal damage has the following four elements:
The accused destroyed or damaged property;
The property belonged to another;
The accused intended to destroy or damage property;
The accused did not have a lawful excuse for his or her actions.
Destroying or Damaging Property
The first element the prosecution must prove is that the accused destroyed or damaged property (Crimes Act 1958 s197(1)).
What is "property"?
For the purposes of this offence, property is defined as real or personal property of a tangible nature (Crimes Act 1958 s196(1)).
This is specifically stated to include the following objects:
Wild creatures which have been tamed or are ordinarily domesticated;
Other wild creatures or their carcasses that:
Have been reduced into possession that has not been lost or abandoned; or
Are in the course of being reduced into possession (Crimes Act 1958 s196(1)). 
This definition of property differs from the definition of property that is used in relation to the offence of theft. In particular:
It excludes intangible property (cf s71(1)); and
It does not restrict the circumstances in which real property may be the subject of the offence (cf s73(6)).
What does it mean to "destroy or damage" property?
The words "destroy" and "damage" are not defined in the Crimes Act.
Destroying property involves rendering it useless for the purpose for which it exists (A Smith, Property Offences (1994), 835).
Damage involves a permanent or temporary alteration to the physical integrity of the property (Grajewski v DPP  HCA 8, ).
A temporary interference or obstruction in the operation of property, which does not interfere with its physical integrity, does not constitute damage (Grajewski v DPP  HCA 8, , ).
Historically, some cases have held that damage occurs where there is a permanent or temporary reduction in the functionality, utility or value of the object (cases). In Grajewski v DPP, the High Court held that this did not give rise to an alternative meaning of damage. Instead, it held that those earlier cases all involved inference with the functionality, utility or value of the object by physical alteration to the integrity of the property, even if that alteration was temporary (Grajewski v DPP  HCA 8, ).
The High Court has rejected a test of “temporary functional derangement” as a criterion for determining criminal damage of property (Grajewski v DPP  HCA 8, ; c.f. Samuel v Stubbs (1972) 4 SASR 200; R v Heyne (unreported, Court of Criminal Appeal of New South Wales, 18 September 1998)).
While rendering property inoperative may be a consequence of damage, it does not itself constitute damage to property. For property to be "damaged", there must have been some kind of interference with the integrity of the property. Cases have therefore drawn a distinction between letting the air out of a tire and attaching a wheel clamp. In the former case, the physical integrity of the tyre is altered, whereas in the latter case, there is no damage unless the clamp physically alters the tyre, even if the vehicle remains inoperable while the clamp is in place (Grajewski v DPP  HCA 8, , . See also Drake v DPP  Crim LR 855; Lloyd v DPP  1 All ER 982; R v Mitchell  RTR 14).
Mere interference with the safe operation of property, without any alteration to the physical integrity of the property, is not damage. Therefore, acts such as tying a person to a bulldozer, or climbing onto a crane, are not acts of criminal damage. In each case, the bulldozer or crane remains functional, but is not operated because of the operator’s desire not to injure the protester (Grajewski v DPP  HCA 8, ).
Property may be "damaged" by virtue of being defaced, even if the operation of the item in question is not affected. Whether a defaced item has been "damaged" is a question of fact for the jury (R v Zische  1 Qd R 240; Roe v Kingerlee  Crim LR 735; Hardman v Chief Constable of Avon & Somerset  Crim LR 330).
Removing part of an object, such as by dismantling or sabotaging a machine, may also constitute "damage", even if there is no damage to the individual components. However, much will depend on whether the accused has been charged with damaging the machine itself, or the components (R v Nesbitt  QCA 333; R v Zische  1 Qd R 240; R v Fisher (1865) LR 1 CCR 7; but compare R v Nyawo (1966) 2 SA 61).
While the property that is damaged must be tangible (see "What is property?" above), the damage does not need to be tangible. Erasure of electronic data may therefore constitute criminal damage (see Cox v Riley (1986) 83 Cr App R 54; R v Whitely (1991) 93 Cr App R 25).  Such activity is also now covered by the specific offences in Subdivision 6 of Part I of the Crimes Act 1958. 
It is possible to damage real property. For example:
A fixture or the land itself may be physically harmed, either temporarily or permanently; or
The land may be physically altered, such as by covering previously clear land with waste materials (McIntosh v Shelley (1908) 25 WN (NSW) 188; R v Maund (1866) 3 WW & A'B (L) 96; R v Henderson & Battley, Court of Appeal Criminal Division, 29/11/1984; Grajewski v DPP  HCA 8, -).
When proving that an item was damaged, it is not necessary to show that there were costs associated with repairing the item. Costs of repairs are merely evidence that may show that the item was damaged (R v Previsic  VSCA 112; R v Zischke  1 Qd R 240).
Destroying or damaging property by omission
While this element will usually be proven by establishing a positive act, it is possible for a person to destroy or damage property by omission (R v Miller  2 AC 161).
This may occur where the accused has created a dangerous situation, and has a duty to take action within his or her capabilities to address the dangers he or she has created. The first element of the offence will be met if the prosecution can prove that the accused knowingly failed to act in the way he or she was required to, and as a result property was damaged or destroyed (R v Miller  2 AC 161).
It is not necessary to show that the accused directly damaged or destroyed the property in question. This element may be met where the accused sets off a chain of events which lead to the property being damaged or destroyed (R v Hayes  QCA 371).
In such cases, it may be necessary to examine the issue of causation. In particular, the jury may need to determine whether the accused’s acts were a "real and substantial cause" of the damage or destruction. See Causation for further information.
Belonging to Another Person
The second element the prosecution must prove is that the damaged or destroyed property either:
Belonged to another person; or
Belonged to the accused and another person (Crimes Act 1958 s197(1)).
When does property "belong" to another person?
Property "belongs" to a person where that person has:
Custody or control of it;
A proprietary right or interest in it (other than one arising from an equitable agreement to grant or transfer an interest); or
A charge on it (Crimes Act 1958 s196(2)).
This includes the interest of a mortgagee (Holden v R (1998) 103 A Crim R 70).
Property which is subject to a trust "belongs" to the trustees and the people who have a right to enforce the trust (Crimes Act 1958 s196(3)).
Property of a corporation "belongs" to the corporation, regardless of any vacancies within that corporation (Crimes Act 1958 s196(4)).
As abandoned property does not "belong" to anyone, this element is not met where the property in question has been abandoned (R v McClymont; Ex parte Attorney-General  2 Qd R 442; R v Webb; Ex parte Attorney-General  2 Qd R 275).
Who must the property belong to?
While the property must belong to "another person", that person does not need to be the sole owner. It is possible for the accused to commit an offence by damaging or destroying property that he or she co-owns with someone else (Crimes Act 1958 s197(1); Howell v Dakin  Tas SR 142).
While this element requires the prosecution to prove that some other person owned the property, it is not necessary to prove the identity of that person (Lodge v Lawton  VR 112. See also R v McClymont; Ex parte Attorney-General  2 Qd R 442).
Where the prosecution alleges that a specific person owns the damaged property and the evidence fails to establish that person’s rights of ownership, the prosecution may need to seek leave to amend the particulars in the indictment (R v McClymont; Ex parte Attorney-General  2 Qd R 442).
Intending to Destroy or Damage Property
The third element the prosecution must prove is that the accused intended to damage or destroy the property (Crimes Act 1958 s197(1)).
Section 197(4) sets out the requirements for proving this element. A person only intends to destroy or damage property if:
One of his or her purposes is to destroy or damage property; or
He or she knows or believes that his or her conduct is more likely than not to result in destruction of or damage to property (see also R v Hayes  QCA 371).
The test in s197(4)(b) differs from the common law recklessness test:
The test in s197(4)(b) requires the jury to find the required consequence to be "more likely than not" (i.e. a greater than 50 percent chance);
The recklessness test requires the jury to find the required consequence to be "probable" or "likely". This may be greater or less than a 50 per cent chance (see Darkan & Ors v R (2006) 227 CLR 373; Boughey v R (1986) 161 CLR 10).
The prosecution must prove that the accused had the required intention at the time he or she did the relevant act or made the relevant omission (Royall v R (1991) 172 CLR 378. See also R v Miller  2 AC 161).
The offender’s age may be relevant when determining whether he or she knew or believed that his or her conduct was more likely than not to result in the property being damaged or destroyed (R v T  1 Qd R 623).
Without Lawful Excuse
The fourth element that the prosecution must prove is that the accused acted without lawful excuse (Crimes Act 1958 s197(1)).
Belief in authority to destroy or damage
A person has a lawful excuse to a charge under s197(1) if, at the time the relevant act was committed, he or she believed that:
The property belonged solely to him or herself (s201(2)(a)(i));
He or she held a right or interest in the property which authorised him or her to engage in the conduct (s201(2)(a)(ii)); or
The people he or she believed were entitled to consent to the destruction or damage had consented, or would have consented if they had known the circumstances of the destruction or damage (s201(2)(a)(iii)).
Each of these excuses depend on the accused having held a particular belief at the relevant time. As long as that belief was honestly held, it does not matter whether it was:
Accurate (R v Smith  QB 354; R v Waine  1 Qd R 458); or
Justified (Crimes Act 1958 s201(3)).
Belief that damage was necessary to protect property
A person has a lawful excuse to a charge under s197(1) if he or she engaged in the conduct in order to protect property belonging to him or herself or another, or a right or interest in property which was or which he believed to be vested in himself or another, and at the time of such conduct he or she believed that:
The property, right or interest was in immediate need of protection; and
The means adopted or proposed to be adopted to protect the property, right or interest were or would be reasonable in all the circumstances (s201(2)(b)).
Scope of s201(2)(b)
The wording of s201(2)(b) draws a distinction between "property" and "rights or interests" in property:
In the case of "property", the excuse only applies to property that belongs to the accused or another person. It does not apply to property the accused believes belongs to him or herself or someone else.
In the case of "rights or interests" in property, the excuse applies both to rights or interests that actually vest in the accused or another person, or that the accused believes to vest in him or herself or someone else.
A "right or interest" in property is stated to include any right or privilege in or over land, whether created by grant, licence or otherwise (Crimes Act 1958 s201(4)).
Consequently, the excuse extends to protecting rights or interests such as easements or rights of way (see Chamberlain v Lindon  EWHC Admin 329).
As the property must belong to the accused or another person, the excuse does not apply to actions taken to protect abandoned property (see Cresswell & Anor v DPP  EWHC 3379 (Admin)).
As the excuse uses the definition of "property" contained in s196(1) (see "What is ‘property’?" above), it also does not apply to actions taken to protect things that falls outside the scope of that definition (e.g., intangible property and wild animals) (Cresswell & Anor v DPP  EWHC 3379 (Admin)).
Requirements of s201(2)(b)
The accused can only rely on the defence in s201(2)(b) of the Crimes Act 1958 if he or she:
Acted in order to protect the relevant property, right or interest;
Believed that the property, right or interest was in immediate need of protection, and
Believed that the means of protection adopted were reasonable in the circumstances (Crimes Act 1958 s201(2)(b)).
The jury must objectively assess whether the accused acted to protect the relevant property, right or interest. A mere assertion by the accused that his or her actions were done for such a purpose is not conclusive (R v Jones & Ors  EWCA Crim 1981; R v Hunt (1978) 66 Cr App R 105).
As long as the accused honestly believed the property was in immediate need of protection, and that the means used to protect the property were reasonable, it is immaterial whether those beliefs were justified (Crimes Act 1958 s201(3); R v Jones & Ors  EWCA Crim 1981).
When assessing the reasonableness of the accused’s conduct, the jury must take into account the circumstances which led to the need to protect the relevant property, right or interest. For example, when a person illegally leaves his or her car in a location where it may be immobilised using a wheel clamp, it will generally be unreasonable to protect his or her interest in the car by damaging or destroying the clamp, rather than paying the cost to have the clamp removed (Drake v DPP  Crim LR 855; Lloyd v DPP  1 All ER 982; R v Mitchell  RTR 14).
Interference with a right or interest may give rise to an ongoing and immediate need to protect the right or interest. The fact that the accused had taken other steps to try to protect the right or interest prior to damaging the property (e.g., he or she had entered into negotiations with the owner of the property) does not necessarily mean that the right or interest was not in immediate need of protection (Chamberlain v Lindon  EWHC Admin 329).
Section 201(2)(b) does not allow a person to stop an owner of property from damaging or destroying that property, unless the damage or destruction is itself illegal, or someone else has an interest in the property in question (Cresswell & Anor v DPP  EWHC 3379 (Admin)).
Common law defences and excuses
The lawful excuses spelt out in s201 operate in addition to any other defences or excuses that arise by statute or under the common law (Crimes Act 1958 s201(2), (5)).
There are two common law matters that may be of particular relevance to this offence:
At common law, a person should not be convicted of an offence if he or she believed, upon reasonable grounds, that it was necessary in self-defence to do what he or she did (Zecevic v Director of Public Prosecutions (1987) 162 CLR 645).
In some cases, a person may believe, on reasonable grounds, that it is necessary to damage or destroy property belonging to another person, in order to defend him or herself or another person. In such cases, the person should not be convicted of criminal damage (see, eg., R v Wilkins  EWCA Crim 1126).
Although not clear, it seems that the same principles may also apply if property is damaged or destroyed in order to protect personal property, or to prevent crime (see, e.g., R v McKay  VR 560). However, given the uncertainties in this area, where the relevant act is committed in defence of property, it is likely to be preferable for the accused to rely on Crimes Act 1958 s201(2)(b) (see, e.g., Cresswell & Anor v DPP  EWHC 3379 (Admin); DPP v Bayer  EWHC 2567 (Admin)).
A person will have a lawful excuse to criminal damage if the owner(s) of the property consented to its damage or destruction. The owner of property has the right to damage or destroy his or her own property, or to authorise another person to do so (R v Denton (1982) 74 Cr App R 81).
This excuse will only apply where the accused had the consent of all co-owners. The authority of only one co-owner is not sufficient if there are other co-owners who have not consented (see Howell v Dakin  Tas SR 142).
Even if the relevant act was carried out for an illegal purpose, such as to facilitate fraud against an insurance company, the accused will generally  have a lawful excuse to a charge of criminal damage if the owner consented to the damage or destruction (R v Denton (1982) 74 Cr App R 81). However, he or she may be guilty of another offence, such as Criminal Damage with a View to Gain.
While the prosecution must prove that the owner did not consent to the damage or destruction, the circumstances of the damage or destruction alone may allow the jury to infer a lack of consent (R v Stevenson (1996) 90 A Crim R 259).
 For information on when a wild animal is in the course of being reduced into possession, see Cresswell & Anor v DPP  EWHC 3379 (Admin).
 Electronic data is tangible (and therefore "property") because it is grounded in a physical state, such as a specific pattern of magnetisation in a computer hard drive.
 Subdivision 6 was added by the Crimes (Property Damage and Computer Offences) Act 2003, which implemented the recommendations of Chapter 4 of the Model Criminal Code Report. That report, while recommending the creation of specific offences for interfering with a computer, acknowledged that the offences may overlap with general criminal damage offences.
 Where the owner of the property is a corporation, the consent of a director of the corporation may not be sufficient. A director may not be competent to consent to fraudulent damage or destruction of property owned by the company (R v Appleyard (1987) 81 Cr App R 319).