If you don’t or if you are not wearing sunglasses then you can be prosecuted for careless driving. This can result in an on the spot fine of £100 and three points on your licence or, if it goes to court, nine points and a fine of up to £2,500.
However, if you are wearing sunglasses but they are the wrong type, then you could also be in trouble. In the UK, sunglasses are divided into four categories, depending on how much light they filter out.
Category 4 sunglasses are illegal when driving as they only filter less than 8% of light. All sunglasses sold in the UK must be labelled and clearly show the filter number on them.