Glossary term

Medical defence: In drug-driving discussions, “medical defence” refers to the legal defence available where a specified drug was lawfully prescribed or supplied and taken in accordance with instructions.

EssentialLegal / drivingSource quality: HighLast updated: 29 June 2026

Why this term matters

Patients need the concept, but they also need the limit.

UK medical cannabis context

Department for Transport guidance explains this defence in detail and emphasises that impaired driving remains an offence.

What not to assume

It does not protect a patient who is actually impaired while driving.

Careful wording: Avoid saying “prescribed cannabis means you are legally fine to drive”.

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.