Work, disclosure and workplace testing.

Is there a law against working on a prescribed cannabis-based medicine?

No. There's no UK law that stops you working because you take a prescribed cannabis-based medicine. The same goes for someone on strong painkillers or sleeping tablets. What most workplaces do have is a drug and alcohol policy, and that's what matters day to day. Some policies only bite if you're impaired at work. Others say any positive test is a disciplinary matter unless you've declared a prescription. A few, in safety-critical industries, are stricter still. Read yours. It's usually in the staff handbook, and you're entitled to a copy.

Do I have to tell my employer?

Not automatically. Your medical information is yours. But there are three situations where I'd think hard about telling someone. And the someone I'd tell is occupational health, not your line manager.

• Your job is safety-critical. That means driving for work, operating machinery, working at height, healthcare, or anything where being drowsy could hurt someone. Here your employer has a fair reason to know. If you say nothing and something happens, you'll have no defence.
• Your workplace tests for drugs, randomly or after incidents. THC from a prescribed medicine looks exactly the same on a test as THC from anywhere else. The time to explain the prescription is before the result, not after.
• You need something to change at work because of your condition or your medicine. It might be your hours, your duties, or a later start on the days after a dose. That's an adjustment, and you can't ask for it without saying why.

If none of those apply, you may reasonably decide it's nobody's business. Plenty of patients do.

Telling occupational health

Occupational health exists for exactly this. They're bound by medical confidentiality. They can tell your employer what you can safely do, without sharing your diagnosis. And a note on your file can say "prescribed medication declared, fit for role with the following considerations". On the day a test comes back positive, that note is worth a great deal. Take your prescription evidence and your clinic's advice on timing and driving. Ask them to record that the medicine is prescribed and taken as directed.

Will a workplace drug test show a prescribed medicine?

Yes, if your medicine contains THC. Workplace tests, whether saliva, urine or hair, detect THC and its by-products. They can do so for days or weeks after a dose, depending on the test and how long you've been taking the medicine. They can't tell whether you were impaired at the time. A test is not proof of misconduct. It's a result, and your employer then has to weigh it against their policy. A declared prescription, with evidence, changes that picture completely. An undeclared one is a much harder conversation.

Does the Equality Act protect me?

It may. The law looks at the condition you're being treated for. If it has a substantial, long-term effect on your daily life, it may count as a disability under the Equality Act 2010. Northern Ireland has its own equivalent law. This applies whether or not you think of yourself as disabled, and many long-term physical and mental health conditions can qualify. If yours does, your employer has a duty to make reasonable adjustments. They also must not treat you less favourably because of something arising from your disability, and that can include the medicine you take for it. That's not a licence to be unsafe at work, but it does mean "we don't allow that here" isn't the end of the discussion.

If things go wrong, Acas offers free advice, and a union representative, if you have one, is worth their subscription in this situation. Get advice before you resign or accept anything.

What habits help at work?

A few simple ones make most of the difference.

• Keep a copy of your prescription and your clinic's written advice somewhere you can reach at work.
• Follow the timing advice on dosing and driving.
• If you notice you're drowsy on shift, say so, the same as you would with any other medicine.
• If you're ever asked to test, ask for the result to be reviewed by a medical review officer with your prescription in front of them. That's standard practice in properly run testing.