DVLA Medical Rules for Professional Drivers (2026 Guide): Eyesight, Diabetes & New CGM Allowances
Updated: January 2026
If you are a professional driver in the UK, your licence depends on your health. For 2026, the DVLA has introduced significant updates—most notably for drivers with diabetes—alongside stricter enforcement on eyesight and prescription medication.
Whether you are renewing your Group 2 (HGV/PCV) licence, managing a condition, or preparing for your D4 medical, this guide breaks down exactly what you need to know to stay legal and keep your livelihood safe.
🚨 MAJOR UPDATE: New Diabetes Rules (Nov 2025)
The biggest change to Group 2 medical standards in a decade.
As of November 2025, the DVLA officially updated regulations for drivers with insulin-treated diabetes. You can now use Flash or Continuous Glucose Monitoring (CGM) systems to monitor your blood sugar levels while driving.
The New 2026 Rules for Insulin-Treated Drivers:
- CGM is Permitted: You may use a standard CGM or Flash GM device (like Libre or Dexcom) to check your glucose levels.
- The “Backup” Rule: You must still carry a finger-prick capillary glucose meter and test strips with you at all times.
- When to Finger-Prick: You must perform a manual test if your glucose level is 4.0 mmol/L or below, or if your symptoms do not match the CGM reading.
⚠️ Critical Warning: If your reading is below 4.0 mmol/L, you must stop driving immediately, treat the hypo, and not drive for at least 45 minutes after your blood glucose has returned to normal.
Group 2 Medical Renewal Requirements (Age 45 & 65 Rules)
The rules for when you need a medical depend entirely on your age. Missing these dates can lead to your entitlement being revoked automatically.
| Age Bracket | Requirement | Frequency |
|---|---|---|
| Under 45 | Initial D4 Medical to obtain provisional entitlement | Once (valid until age 45) |
| 45 – 64 | Full D4 Medical Assessment | Every 5 years |
| 65+ | Full D4 Medical Assessment | Annually |
The D4 Medical Form
You must download the D4 Medical Form (Gov.uk) and have it filled out by a doctor.
- Pro Tip: You do not have to use your own GP. Many private providers offer this service for £50–£70, whereas GP surgeries can charge significantly more and have longer waiting times.
- Vision: If your doctor cannot perform the eyesight test, you must have the vision section completed by an optician before you send the form.
Eyesight Standards: The “Grandfather Rights” Trap
Eyesight is the most common reason for failure. The standards for HGV/PCV drivers are much stricter than for car drivers.
The 2026 Standard
- Visual Acuity: You must have a visual acuity of at least 6/7.5 in your better eye and 6/60 in the other eye (with glasses/contacts if needed).
- Field of Vision: You must have a horizontal visual field of at least 160 degrees, with an extension of at least 70 degrees left and right and 30 degrees up and down.
Do you have “Grandfather Rights”?
If you passed your HGV test before 1 January 1997, milder eyesight rules may apply to you, but only if your sight has not worsened significantly. If you lose sight in one eye, you may be barred from holding a Group 2 licence entirely unless you meet strict adaptation criteria.
Heart Conditions & Sleep Apnoea (OSA)
Obstructive Sleep Apnoea (OSA)
Traffic Commissioners are increasingly strict on “tired driving.” OSA causes interrupted breathing during sleep, leading to dangerous daytime fatigue.
- Must Report: If you have Moderate or Severe OSA combined with excessive sleepiness.
- The “Fast-Track” Route: Many NHS trusts now have a fast-track system for professional drivers. If diagnosed, you can usually keep driving if you can prove you are using a CPAP machine and your symptoms are controlled.
- View official DVLA guidance on OSA
Cardiac Rules
If you suffer a heart attack (myocardial infarction), you must stop driving immediately.
- Group 2 Rule: You must stop driving for at least 6 weeks.
- Return to Drive: You can only return after passing a functional test (e.g., treadmill exercise test) and getting approval from your specialist.
Mental Health & Prescription Drugs (The “Medical Defence”)
It is illegal to drive with certain drugs in your system above specified limits. However, there is a “Medical Defence” for prescription users.
The Law
You can drive while taking legal medication (e.g., Diazepam, Methadone, Morphine) IF:
- It has been prescribed to you.
- You are taking it exactly as directed.
- Crucially: It does not impair your ability to drive.
Warning: If you are drowsy, dizzy, or have slowed reaction times, do not drive. “I was following the prescription” is not a defence if you were visibly impaired and caused an accident.
Frequently Asked Questions (FAQ)
Q: Can I drive while my medical application is with the DVLA?
A: Usually, yes—under “Section 88” of the Road Traffic Act. You can continue driving if your doctor says you are fit and you have a valid application pending, provided your licence hasn’t been previously revoked.
Q: Do I need to tell the DVLA about high blood pressure?
A: Only if your resting blood pressure is consistently 180/100 mmHg or higher. You must stop driving until it is treated and reduced.
Q: How do I report a condition?
A: Use the online declaration service on GOV.UK. It is faster than paper forms.
Stay Compliant, Keep Your Licence
Medical rules are there to protect you and other road users. Hiding a condition is never worth the risk—insurance validation often relies on you being medically compliant.
Need to update your CPC training while sorting your medical?
Ensure your Driver CPC card doesn’t expire. Contact the Transcom National Training team today for up-to-date support and courses.
Disclaimer: This guide is for information only and based on DVLA guidance as of January 2026. Always refer to official GOV.UK Medical Standards for legal advice.
