Under the UK Highway Code Rule 110 , you should only flash your headlights to let other road users know you are there.
: These should only be used when a vehicle is stationary and causing a temporary obstruction, or to warn following drivers on motorways of an obstruction ahead. Fishing Equipment uk flashers
: Flashing headlights to warn others of speed cameras or police checkpoints can lead to fines of up to £1,000 for obstructing police duties. Under the UK Highway Code Rule 110 ,