Glossary term

Zero-tolerance limit: In everyday discussion, “zero-tolerance limit” describes the very low specified legal limits applied to commonly abused drugs in drug-driving law, including cannabis (THC).

UsefulDriving / legalSource quality: HighLast updated: 29 June 2026

Why this term matters

Patients often hear the phrase even though the legal framework is more precise than that shorthand.

UK medical cannabis context

DfT says THC sits in the first group of specified drugs with low limits, while also explaining the statutory medical defence and the separate offence of driving while impaired.

What not to assume

It should not be used to imply there is no medical defence at all; there can be one if the medicine is prescribed and taken correctly.

Careful wording: Avoid oversimplifying the law to “any THC equals automatic conviction”.

Related glossary terms

Related MCPH pages

Sources and review notes

This entry is educational vocabulary, not medical advice. Suitability, prescribing, product choice and monitoring belong with a qualified clinician or pharmacist.