Driving in adverse weather conditions
You MUST use headlights when visibility is seriously reduced, generally when you cannot see for more than 100 metres (328 feet). You may also use front or rear fog lights but you MUST switch them off when visibility improves (see Rule 236).
Law RVLR regs 25 & 27
Wet weather. In wet weather, stopping distances will be at least double those required for stopping on dry roads. This is because your tyres have less grip on the road. In wet weather
you should keep well back from the vehicle in front. This will increase your ability to see and plan ahead
if the steering becomes unresponsive, it probably means that water is preventing the tyres from gripping the road. Ease off the accelerator and slow down gradually
the rain and spray from vehicles may make it difficult to see and be seen
be aware of the dangers of spilt diesel that will make the surface very slippery
take extra care around pedestrians, cyclists, motorcyclists and horse riders.