People who buy drugs to share with friends could avoid prison under guidance that also recognises medical use of cannabis

Recreational drug users who naively buy small quantities to share with their friends could avoid jail under sentencing guidelines for drug offences published on Tuesday.

The sentencing council also spells out explicitly, for the first time, that the medical use of cannabis for serious conditions should be recognised by the courts as a mitigating factor when sentencing offenders.

The official guidance for the courts, which comes into force next month, also recommends a less draconian approach to the sentencing of "drug mules".

The council says it recognises that mules are often women who have been coerced or exploited by organised criminals: judges should take a six-year prison sentence as their "starting point", rather than the current 10 years, when considering cases of mules playing a "lesser role" in bringing in up to 1kg of heroin or cocaine.

The first comprehensive guidelines, which reflect the current practice in the courts, recommend no change in sentencing for possession or supplying illegal drugs. A criminal who sells drugs in the street for a profit can expect to be sent to prison, with those dealing heroin or cocaine likely to get at least four and a half years.

Those who sell drugs to anyone under 18 are to be treated more severely, and there are to be longer sentences for industrial levels of production, for example, in cannabis factories.

The guidelines retreat from prescribing precise amounts of each drug to gauge how serious an offence is. Instead, quantities of drugs are classified into four broad categories, with sentencing determined by whether the offender played a leading, significant or lesser role.

The lowest category includes up to 100g of cannabis, 5g of heroin or cocaine, and 20 tablets of ecstasy. A "leading role" covers organising, buying and selling on a commercial scale, with substantial links to others in the chain, expecting substantial profits and using business as a cover.

The council cites an example of two university students sharing a flat who share the cost of 20 ecstasy tablets. The one who buys them is arrested before he can give them to his flatmate but he admits they both provided money and would have shared them. The guidelines say the "starting point" for the court for such an example should be 18 months in jail, but the bottom of the range would be an 18-month community order.

Lord Justice Hughes of the sentencing council said: "This guideline reinforces current sentencing practice. Drug dealers can expect substantial jail sentences."

Niamh Eastwood of Release, the drugs advice charity, said it welcomed the council's decision to drop its initial proposal to determine sentence on the basis of the quantity involved for possession offences, and the reduced sentences for mules.

"The whole system of sentencing for drug offences needs significant reform as the reality is that the UK gives longer sentences for supply than most other countries," she said, pointing out that the starting point for importing a "medium amount" of heroin was 11 years while the starting point for a rape was five years.