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Definition of 'possession'

There is a lot of law about the definition of possession which is defined in section 4 of the Controlled Substances Act 1984 (SA) as including having 'control over the disposition of the substance or thing' as well as 'having joint possession of the substance or thing'.

Intending to control the disposition of substances in another person's custody will also imply possession.

Elements of possession

Possession, incudes two elements:

  • being in physical control of the drug (includes joint control with another / others); and
  • knowledge (or intention) of having the drug.

Both elements must exist before a person can be found guilty.

What is physical control?

Physical control requires custody; and control; or the ability to exercise control over the goods at will, including control over their disposition.

A person will usually have possession of a drug if it is found in that person's pocket or hand or bedroom, where the person alone has access to it. However, as control also includes disposition this can include anything from throwing the substance away, to never actually having had physical possession but possessing the ability to say where the substance should be placed.

A person possessing a container is usually assumed to be in possession of its contents although this can be challenged if the person was mistaken about its contents.

Joint possession with another or others is also now specifically covered under the Controlled Substances Act 1984 (SA) definitition [s 4]. This might be the case if for example, the substance is found in a car with a group of people and they are all have control of the substance.

Possession is not necessarily the same as ownership

Possession is not necessarily the same as ownership, although ownership often can be used to show possession. Possession will depend on the circumstances of each case. For example, where a drug is found in a communal part of premises, (where people come and go), the prosecution will have difficulty in proving precisely who is in possession of the drug. However, prosecution can charge people together and allege that they were in joint possession of the drug.

[ See further a key case on possession and controlled substances: Bourne v Samuels (1979) SASR 591]


To be guilty of possession the defendant must be shown to have known two things:

  • first, that they knew the substance was in their custody and control, and
  • secondly, that they knew the substance was a prohibited one and that possession of it is contrary to the laws relating to illegal drugs.

Even where the defendant did not know precisely what the drug was, if it can be shown that he or she knew that the substance was an illicit one this will be sufficient to establish the offence. It may be possible to draw the conclusion that a person had this knowledge from the circumstances surrounding the offence.

It is not necessary to have actual knowledge that a substance is illicit or prohibited, it can be enough that the defendant was aware of the likelihood that a concealed substance was a prohibited drug.

Defence of honest and reasonable mistake:

It is a defence to prove an honest and reasonable mistake about the nature of the substance possessed.


To be guilty of possession a person must also intend to exercise control over the drug, as well as being in a position to do so.

For example, if a person has drugs in her or his room, someone else who knows they are there, but does not intend to exercise any control over the drugs, does not possess them.

It is not an offence simply to be close to drugs, or to know where the drugs are, without also having an intention to possess them.

Definition of 'possession'  :  Last Revised: Tue Feb 10th 2015
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