Drug supply cases can involve much more evidence than the controlled drugs themselves. Police and prosecutors may examine mobile phones, financial records, cash, packaging, weighing scales, forensic material, surveillance footage, witness accounts and documents when attempting to establish whether somebody was involved in supplying controlled drugs.

In cases involving possession with intent to supply (PWITS), evidence may also be used to establish what the defendant intended to do with drugs found in their possession.

This distinction is important. Finding controlled drugs may provide evidence of possession, but proving supply or an intention to supply can require a much broader examination of the surrounding circumstances.

Under the Misuse of Drugs Act 1971, offences include supplying a controlled drug, being concerned in its supply and possessing a controlled drug with intent to supply it to another person.

So, what evidence can be used in a drug supply prosecution?

This article examines the main categories of evidence that may feature in drug supply cases in England and Wales and explains why the context surrounding that evidence can be just as important as the evidence itself.

What Does the Prosecution Have to Prove?

The exact matters the prosecution must establish depend on the offence charged.

For possession with intent to supply, section 5(3) of the Misuse of Drugs Act 1971 is particularly important. The prosecution must establish the relevant possession and the intention to supply the controlled drug to another person.

For an allegation of actual supply, the issues are different because prosecutors may seek to prove that a supply has already occurred.

Crown Prosecution Service guidance makes an important distinction between evidence of past supply and evidence demonstrating an intention to make a future supply.

The evidence in a particular case must therefore be considered in relation to the specific offence alleged.

The Controlled Drugs Themselves

Unsurprisingly, the substances recovered by police can form a central part of a drug prosecution.

Investigators will need to establish what has actually been seized.

Depending on the circumstances, forensic examination may be used to identify a substance as a controlled drug.

The type of substance can be important because controlled drugs are classified as Class A, Class B or Class C, and the classification can significantly affect the potential consequences of conviction.

The amount recovered can also become important evidence, particularly in PWITS cases.

Quantity of Drugs

Quantity is frequently relied upon when prosecutors seek to distinguish personal possession from possession with intent to supply.

CPS guidance identifies possession of a quantity inconsistent with personal use as a factor from which an intention to supply may potentially be inferred.

The prosecution might therefore argue that the amount recovered is greater than would reasonably be expected for personal consumption.

However, quantity should not automatically be treated as conclusive proof of supply.

Its significance depends on the substance, the individual circumstances and the other evidence available.

The defence may challenge whether the amount genuinely supports the inference alleged by the prosecution.

Packaging and Individual Portions

How controlled drugs are stored and packaged can also become significant.

CPS guidance identifies drugs prepared for sale as potential evidence of an intention to supply. In particular, drugs divided into small portions and individually wrapped may support an inference that onward distribution was intended.

Police may therefore document:

• The number of packages recovered;
• Whether the packages are similar in size;
• How the drugs have been wrapped;
• Where the packages were discovered; and
• Whether additional packaging materials were present.

The prosecution may argue that the overall presentation is consistent with preparation for supply.

However, the existence of multiple packages does not necessarily answer every issue in the case. Questions may remain about who prepared them, who controlled them and what the defendant knew or intended.

Drug Purity

The purity of a controlled drug may also have evidential significance.

CPS guidance identifies possession of uncut drugs or drugs in an unusually pure state as a factor that can potentially suggest proximity to a manufacturer or importer.

Forensic analysis can therefore potentially provide information beyond simply confirming the identity of a substance.

The significance of purity will depend on the particular prosecution case and how that evidence relates to the defendant.

Different Types of Controlled Drugs

Possession of several different drugs can also be relied upon by prosecutors.

CPS guidance recognises that possession of a variety of controlled drugs may indicate sale rather than personal consumption.

Again, this is an inference rather than an automatic conclusion.

The prosecution must establish the relevance of the substances and connect them to the defendant and the alleged offence.

Weighing Scales

Weighing scales frequently feature in allegations of drug supply because prosecutors may argue that they were used to prepare quantities for distribution.

The significance of scales can depend on several surrounding factors.

For example, investigators may consider where they were discovered and whether they appear to be connected to the drugs.

CPS guidance specifically identifies weighing scales as potentially relevant drug-related equipment, while also recognising that an item’s presence may sometimes be consistent with ordinary domestic use.

The context is therefore essential.

Bags, Foil and Packaging Materials

Small bags, wraps and foil can also form part of the evidence.

The prosecution may argue that packaging materials discovered alongside controlled drugs indicate preparation for future distribution.

However, many packaging materials also have legitimate everyday uses.

Finding plastic bags in a kitchen, for example, would not necessarily have the same evidential significance as discovering particular materials alongside individually prepared quantities of controlled drugs and other evidence alleged to relate to supply.

The court must consider what reasonable inference can actually be drawn from the circumstances.

Cutting Agents and Other Equipment

CPS guidance also identifies cutting agents among the types of drug-related equipment that may support an inference of intent to supply.

The evidential significance will depend on the nature of the substance and its connection with the drugs and defendant.

Police may seek forensic analysis where appropriate.

The prosecution may then attempt to use the results alongside the remaining evidence to establish the alleged activity.

Mobile Phone Evidence

Mobile phones can be one of the most significant sources of evidence in modern drug investigations.

Subject to the applicable legal rules and investigative powers, police may obtain and examine digital material relevant to the alleged offence.

Communications can potentially be relied upon where prosecutors argue that they demonstrate involvement in supply.

However, mobile phone evidence can raise complicated questions.

A phone being found in someone’s possession does not necessarily establish that they personally created every piece of information stored on it.

Questions may arise concerning:

• Ownership of the device;
• Who had access to it;
• Who was using it at a particular time;
• Whether multiple people used the same phone;
• The meaning and context of communications; and
• Whether particular communications actually relate to the alleged drugs.

Attribution and interpretation can therefore become important issues.

Call Records and Contact Patterns

Investigators may also consider communications patterns where they are relevant and lawfully available.

The prosecution may seek to place communications into a timeline alongside other evidence.

However, evidence showing communication between two people does not necessarily establish what they discussed.

The significance of contact evidence therefore depends on its context and on the other material available in the case.

Digital Evidence Beyond Messages

Phones and other electronic devices can potentially contain many forms of data.

Depending on the circumstances of the investigation and the material lawfully obtained, relevant digital evidence may extend beyond conventional text messages.

The key question remains whether the particular material is relevant and admissible and what it actually establishes about the defendant’s alleged conduct.

Digital evidence can be persuasive, but it must still be interpreted accurately.

Cash as Evidence

Cash is another common feature in drug investigations.

Where significant sums are discovered, police may investigate their source.

However, the evidential significance of cash in a PWITS case needs to be understood carefully.

CPS guidance explains that money found on a defendant is not necessarily evidence of a future intention to supply. Money may provide evidence relating to previous supply, but money on its own does not establish a future intent to supply.

Large amounts of money may nevertheless be admissible where they have genuine probative significance to an issue in the case.

The defence may also provide evidence of a legitimate source of funds.

Financial Evidence

Drug supply investigations can extend beyond physical cash.

Where relevant and lawfully obtained, financial evidence may be examined to establish whether transactions or patterns support the prosecution’s allegations.

Financial evidence requires context.

The existence of payments does not automatically establish that those payments relate to controlled drugs.

Investigators and prosecutors may therefore attempt to connect financial activity with other evidence in the case.

Conversely, the defence may identify legitimate explanations for transactions or funds that initially appeared suspicious.

Diaries, Notes and Alleged Dealer Records

Written documents can also become important.

CPS guidance identifies diaries or other documents containing information tending to confirm drug dealing as potentially relevant evidence of a future intention to supply.

For example, prosecutors may rely on records they say contain customer telephone numbers alongside quantities or descriptions of drugs.

However, documents do not always explain themselves.

A notebook containing names and numbers may have an entirely legitimate purpose.

The prosecution must establish why the document is relevant and what reasonable conclusions can be drawn from it.

Surveillance Evidence

Surveillance can potentially provide direct evidence relevant to drug supply.

Depending on the investigation, police evidence may include observations or recordings of relevant conduct.

Surveillance may be used alongside other evidence to construct a chronology of events.

For example, prosecutors might attempt to connect observations with drugs subsequently recovered or other evidence obtained during the investigation.

As with other evidence, what surveillance actually shows can be disputed.

The fact that people meet or travel together does not necessarily establish criminal activity without additional context.

CCTV and Video Evidence

CCTV or other video footage can also become relevant.

Footage may help establish where somebody was at a particular time or show interactions that investigators consider important.

However, interpretation remains necessary.

Questions can arise about image quality, identification, timing and what can genuinely be seen.

The prosecution may need to demonstrate how the footage fits with the rest of its case rather than relying on assumptions about ambiguous behaviour.

Witness Evidence

Witness testimony can be another important source of evidence.

A witness might give evidence about an alleged supply, conversations, observations or other relevant events.

The reliability of witness evidence can be challenged in court.

Factors may include the witness’s ability to observe what happened, the accuracy of their recollection, inconsistencies between accounts and whether other evidence supports or contradicts their version of events.

Witness evidence must therefore be assessed in the context of the entire case.

Admissions and Police Interviews

What a suspect says during a police interview can become significant evidence.

CPS guidance identifies admissions as a form of direct evidence through which an intention to supply may potentially be proved.

During an investigation, questions may concern matters such as possession, ownership, the reason drugs were present, mobile phones, cash, packaging and relationships with other individuals.

The answers may later be relied upon by the prosecution.

This is one reason obtaining legal advice before and during a police interview can be important.

Forensic Evidence

Forensic science can contribute to drug cases in several ways.

Most obviously, forensic analysis can help establish whether a recovered substance is a controlled drug.

Depending on the circumstances, forensic evidence may also assist with other issues concerning physical exhibits.

However, it is important to distinguish between proving contact with an object and proving criminal intent.

Even where forensic evidence connects a person to a particular item, the prosecution may still need to establish what that connection means in the context of the offence charged.

Evidence Found in a Property

The location in which evidence is discovered can be particularly important.

A drug supply investigation may involve searches of houses, flats or other premises.

Where evidence is discovered in a property occupied by several people, questions can arise over who knew about it and who exercised control over it.

CPS guidance specifically warns that where drugs are found in premises occupied by more than one person, mere knowledge of their existence is not enough to establish joint possession.

The prosecution must establish the involvement required for the offence charged against each defendant.

Evidence Found in a Vehicle

Similar issues can arise when drugs are found in a car containing several occupants.

Simply being inside a vehicle in which controlled drugs are discovered does not automatically make every occupant jointly responsible for them.

Investigators may examine where the drugs were located, who controlled the vehicle, the movements of those involved and other relevant evidence.

The prosecution must establish the particular defendant’s participation rather than relying solely on association or proximity.

Evidence Involving Several Defendants

Drug supply cases sometimes involve multiple defendants.

In such cases, prosecutors may allege that individuals played different roles in a wider operation.

However, association with another person suspected of drug offences is not automatically proof of participation.

The CPS guidance states that, in joint-possession cases, prosecutors need evidence demonstrating that each defendant participated in the offence.

Evidence may therefore need to be considered separately for each accused person.

Evidence of Past Supply vs Future Intent

This distinction is particularly important in PWITS prosecutions.

Possession with intent to supply concerns an intention to make a future supply.

Evidence relating solely to previous dealing does not automatically prove what somebody intended to do with drugs currently in their possession.

For example, CPS guidance specifically recognises that cash may potentially indicate past supply without, on its own, establishing future intention.

Prosecutors must therefore connect the evidence to the offence actually charged.

Is Circumstantial Evidence Enough?

A drug supply case does not necessarily require a single piece of direct evidence.

The prosecution can rely on circumstantial evidence.

Indeed, CPS guidance indicates that an intention to supply may often be inferred from a combination of factors.

A prosecution case might therefore involve several categories of evidence which prosecutors say collectively establish the alleged activity.

The defence can challenge individual pieces of evidence as well as the overall inference the prosecution asks the court to draw.

Can Evidence Have an Innocent Explanation?

Yes.

An important part of analysing any criminal case is considering alternative explanations.

Cash can come from legitimate sources.

A phone can be used by more than one person.

Scales can have ordinary domestic uses.

Names and numbers in a notebook can relate to lawful activity.

A person can be present in a property without controlling everything inside it.

The existence of an alternative explanation does not automatically defeat a prosecution, but it can be highly relevant when assessing whether the prosecution has proved the allegation.

How Is Evidence Challenged in a Drug Supply Case?

There is no universal defence strategy because every case is different.

A criminal defence solicitor may need to examine:

• How the evidence was obtained;
• Whether it is admissible;
• Whether the defendant can actually be linked to it;
• Whether digital evidence has been properly attributed;
• Whether the prosecution’s interpretation is justified;
• Whether forensic evidence supports the allegation;
• Whether the quantity genuinely indicates supply;
• Whether there are legitimate explanations for cash or financial activity;
• Whether possession or control can be established; and
• Whether individual items prove what prosecutors claim they prove.

The overall prosecution case must then be considered rather than viewing individual pieces of evidence in isolation.

Why Evidence Can Affect Sentencing

Evidence gathered in a drug investigation can remain important even after a conviction.

Under the Sentencing Council guideline for drug supply and PWITS offences, courts assess factors including the offender’s role and the harm involved.

Roles are categorised as leading, significant or lesser depending on the circumstances.

Quantity is central to the assessment of harm.

Evidence about organisation, financial gain, influence over others and the extent of a defendant’s involvement may therefore affect how their role is assessed.

This is why accurately determining what the evidence proves can be important at every stage of proceedings.

Conclusion

Drug supply prosecutions can rely on a wide range of evidence.

The controlled drugs themselves are only one part of the picture. Quantity, purity, packaging, scales, other equipment, mobile phones, financial evidence, cash, documents, surveillance, CCTV, witness testimony, police interviews and forensic evidence can all potentially become relevant.

However, evidence must always be considered in context.

The presence of an apparently suspicious item does not necessarily establish its purpose, ownership or connection to a particular defendant. This can be particularly important where several people occupy the same property or travel in the same vehicle.

In possession with intent to supply cases, there is also an important distinction between evidence of previous drug activity and evidence demonstrating an intention to make a future supply.

Ultimately, the prosecution must prove the particular offence charged. Evidence can be examined, interpreted and challenged, and the strength of a drug supply case will depend on the facts and circumstances as a whole.

Anyone accused of supplying controlled drugs or possession with intent to supply should seek specialist criminal defence advice as early as possible. A solicitor can examine the evidence, advise on the allegations and provide representation throughout the investigation and any subsequent court proceedings.