Driving takes a lot of concentration and you have to be fully in control of your vehicle at all times, so if you have a medical condition you may find that you are limited when driving.
If you are epileptic, there is a chance that you could have a fit behind the wheel, and for this reason the DVLA ask you to be fit free for a year before they will issue you with a driving licence. They will then review you and see that you are fit for driving. You will then have your licence reviewed along the course of its duration, and you will need a medical review at the end of this time to make sure there are no changes.
Narcolepsy is another condition that you need to inform the DVLA about, as there is a risk that the driver will fall asleep when driving. If you suffer from narcolepsy then you should stop driving straight away, and you will be assessed before being granted a shorter licence.
Diabetes sufferers will alos need to inform the DVLA, as you will need to feel the symptoms when your blood sugar is going low. As long as you meet the visual requirements stipulated you should be fine to drive, but it will be a shorter licence.
Angina sufferers are allowed to drive, but if you have had an attack you should refrain from driving until you feel better.
When driving on the roads in the UK< make sure you buy Insurance for Car owners online.