Of all the adverse weather we experience in UK, fog is arguably the most dangerous condition for driving in because it significantly reduces visibility.
Fog lights are designed to help improve visibility but if they are used at the wrong times, they can have the opposite effect. So, when should you use fog lights? Fog lights are only supposed to be used when visibility drops to less than 100m which is roughly the size of a football pitch. In these conditions, you should also be driving more slowly as you will have less time to react to hazards on the road.
Fog lights are extremely bright so if you use them when it is not foggy, you risk causing an accident and you could even be handed a fine. In addition to this, if you were to have an accident in foggy conditions and you were found to not have your fog lights on, your insurance may be invalid.