A Class B substance is a controlled drug in the middle tier of the United Kingdom’s three-level classification system. Under the Misuse of Drugs Act 1971, all illegal drugs are sorted into Class A, B, or C based on the harm they pose, with Class A considered the most dangerous and Class C the least. Class B sits between them, carrying a maximum penalty of 5 years in prison for possession and 14 years for supply.
How the UK Classification System Works
The Misuse of Drugs Act 1971 groups controlled substances into three classes that determine how severely the law treats offences involving them. Class A includes drugs like heroin, cocaine, crack cocaine, LSD, and ecstasy. Class B covers substances viewed as harmful but less immediately dangerous than Class A. Class C includes drugs such as anabolic steroids, benzodiazepines (like Valium and temazepam), and GHB.
The classification is meant to reflect real-world harm to individuals and society, though it has been widely criticized. A government advisory council periodically reviews drugs and recommends reclassifications, but the Home Secretary has the final say on whether to accept those recommendations.
Which Drugs Are Class B
The main substances classified as Class B include:
- Amphetamines (speed), the most well-known Class B drug. However, amphetamines prepared for injection are automatically reclassified as Class A, which carries much harsher penalties.
- Cannabis, which was reclassified from Class B down to Class C in January 2004, then moved back up to Class B in 2009.
- Methamphetamine (crystal meth)
- Barbiturates, a type of sedative
- Codeine, when not in a form legally available on prescription or over the counter
- Synthetic cannabinoids (spice)
The list is not static. Substances are added or moved between classes as the government responds to new evidence about harm or emerging drug trends.
Penalties for Class B Offences
The penalties for Class B drugs are significantly lower than Class A but still serious. According to Crown Prosecution Service sentencing guidelines effective from April 2021:
- Possession: Up to 5 years in prison, a fine, or both. In practice, sentences range from a discharge (no punishment) to 26 weeks in custody depending on the amount, circumstances, and criminal history.
- Supply or intent to supply: Up to 14 years in prison and an unlimited fine. The typical sentencing range runs from a moderate fine up to 10 years in custody.
For comparison, Class A possession carries a maximum of 7 years, while Class C possession tops out at 2 years. Supply penalties for both Class B and Class C share the same 14-year maximum, but Class A supply can result in a life sentence.
The Cannabis Reclassification Saga
Cannabis has the most complicated classification history of any UK drug. In 2002, the government’s Advisory Council on the Misuse of Drugs recommended downgrading cannabis from Class B to Class C. The Home Secretary accepted this, and the change took effect on 29 January 2004.
Almost immediately, political pressure built to reverse the decision. In 2005, the Home Secretary asked the advisory council to reconsider in light of new research linking cannabis use and mental health problems. The council reviewed the evidence and stood by its recommendation, concluding that the risk of an individual developing schizophrenia from cannabis use was “very small” and that cannabis remained “substantially less harmful” than other Class B substances like amphetamines, barbiturates, or codeine. It also noted that reclassification to Class C had not led to any increase in cannabis use among young people.
Despite this advice, the government moved cannabis back to Class B in 2009, a decision driven more by political concerns than scientific consensus. It remains Class B today.
How Class B Differs From Other Countries’ Systems
The UK’s A/B/C system is specific to the Misuse of Drugs Act 1971 and applies in England, Wales, and Scotland. It should not be confused with the American system, where some states use a similar-sounding A through E classification but with entirely different substances and penalties in each category. In the US system, Class B (or Schedule II) typically refers to drugs with high abuse potential that still have accepted medical uses, like certain prescription stimulants and opioids. The labels may look similar, but the legal frameworks and the drugs they cover are quite different.
If you’ve come across the term “Class B substance” in a legal context, checking which country’s law applies is essential, since the same phrase carries different meanings in different jurisdictions.