The Police and CPS will look at all sorts of evidence to decide if someone has committed an offence, and what offence that might be.
Possession of a Controlled Drug
For this offence the drugs themselves are normally the only actual evidence that the police and prosecution will have.
There is no fixed amount that can be said to be for personal use – if you are caught in possession of a particularly large amount of drugs then the police may think that it is too much for your own needs and you could be charged with an offence of possession with intent to supply drugs, which is much more serious. However, your personal situation will be very important - if you use a high dose/quantity of drugs regularly it might be more likely that you will have a greater amount in your possession.
Possession with Intent to Supply (PWITS) a Controlled Drug
The amount of drugs you have in your possession might suggest to the police and prosecution that you are intending to supply them to someone else. However, the amount on its own is not normally enough evidence and the police will always look at what else is found with the drugs, or at your home. If other things that are regularly involved in the supply of drugs are also found, this may suggest that you have the intention to sell or supply drugs. These items can include scales, individual ‘deal bags’, cling film, lists of customers, text messages indicating transactions, and cash.
The police might also check anything that the drugs are wrapped in for fingerprints – especially if you are saying that the drugs don’t belong to you.
Even if caught with a small quantity of drugs statements given by you can be used in evidence; for example, if you say to the police you were holding a ecstasy pill for a friend this could be used to establish intention to supply.
Supply of a Controlled Drug
The amount of drugs is less important if you are caught actually supplying them. Even if you only supply a tiny amount of drugs to someone, you could still be charged with the offence.
The Police will look for the same sort of evidence as for PWITS, but because actual supply needs to have taken place they will also use other types of evidence. This could be CCTV or hidden cameras, or there may be undercover officers in places where drug supply is known to happen. They might even use listening devices (known as a ‘probe’) to record conversations. A common example would be in the car of a suspect. These recordings are allowed to be used as evidence in court. However, the police are not allowed to intercept telephone conversations.
Undercover officers might pretend to be a person buying drugs to prove that someone is selling drugs. The undercover officer will usually have a hidden camera or microphone on them and the deal will be recorded.
An undercover officer can’t force or persuade someone to commit an offence. This would be considered ‘entrapment’ and is where the person wouldn’t have committed the offence without the officer’s encouragement. Any evidence found in this way could be rejected by the Court. However, an undercover officer is allowed to give someone an opportunity to commit an offence by asking them to sell drugs. If someone agrees to this and sells drugs to an undercover officer then this is not entrapment.
Mobile Phone Evidence
The police might look at telephone or computer evidence to prove that a person has the intention to supply drugs or has actually sold them. It is possible to access deleted messages and the police may even download photos saved on the phone to see if there is any evidence of drug supply. They know about codes that people use when discussing drugs and might get an expert to translate any messages.
The police can look at telephone records of calls and texts made and received, and also look at the location they were made. This is known as cell site analysis. For example, if you travel across London using your mobile phone, the police could track your general location if they checked with your network provider. They can’t pinpoint your exact location, for instance to a room in a house, but they will know generally where you have travelled. This sort of evidence is often used in cases where the police believe there are lots of people working together in a conspiracy to sell drugs, because it can show a relationship between them.
Production of a Controlled Drug
As well as drugs themselves, the police will look for evidence that a drug has been produced at a particular place. This will include any equipment or ingredients that could be used to make a drug or to mix with it to bulk it out, or to separate a drug from a different substance.
If you let someone else produce drugs in your property you might be held responsible for it, or could at least be prosecuted for allowing the place to be used for the production of drugs.
The police might check any equipment for fingerprints, especially if you are saying that you are not involved in the production of a drug.
Cultivation/Production of Cannabis
The police will look for certain evidence that might suggest cannabis is being grown. It is often the smell of cannabis that will lead to the police attending or someone reporting it. Other activities that might draw attention are blacked out windows, unusual levels of waste being put out as rubbish, and increased heat emanating from the property (police will ask neighbours about these factors). The police have also contacted energy providers to see if there are unusually high levels of energy being used at a property.
More recently, police are also using equipment to monitor heat being released from houses as this can also be a sign that cannabis is being grown because of the lights that are used. Any of these factors can be enough to establish grounds for a warrant and for the police to enter and search the property.
Cannabis plants will obviously be evidence that is used to show that someone has been growing it. The more plants that are found the more serious the offence will be. The stage the plants are at is also important – they could be seedlings or plants that are ready to be cut.
Cannabis can be grown quite simply or using equipment known as hydroponics. Although it is illegal to grow cannabis plants even if it is only for your own use, it is not illegal to be in possession of the equipment that is used to grow cannabis. It is legal to buy and keep hydroponics equipment but if you then choose to use this equipment to grow cannabis this will be a criminal offence. Using a hi-tech setup will be seen as a more serious offence.
As well as plants and equipment, the police will also look for evidence of previous grows including dried or drying cannabis, and even string that was used to tie plants before, which will suggest that this is not a one-off offence.
Often the police evidence will estimate the yield or the number of rotations that have occurred in order to show the scale of the operation, which is important for sentencing purposes. This evidence may be in dispute, and even if you plead guilty to the offence, you can challenge the police evidence in court. This is often done by the defence instructing an expert witness who can provide testimony to the court about the scale of the operation, including the potential useable cannabis (it is usually only the dried, female flowering heads that are counted) that could have been yielded from the plants. There are also sometimes grounds to challenge what the prosecution claim would have been the intention for the yield; for example, whether or not it would likely have been commensurate with personal consumption.
If you let someone else grow cannabis in your property you might be held responsible for it, or could at least be prosecuted for allowing the place to be used for the production of cannabis.
The police may also check any equipment for fingerprints to see who has been in contact with it, especially if you are denying that you are involved in growing cannabis.