Motorists might think it's a good deed but it could result in £1,000 fine

Motorists who think they're doing a good deed on the roads could actually end up with a hefty fine and points on their licence. Drivers who flash their headlights or gesture with their hands to warn fellow road users about the position of speed cameras are actually breaking the law.

The Highway Code's rule 110 states: "Only flash your headlights to let other road users know that you are there. Do not flash your headlights to convey any other message or intimidate other road users."

Under section 89 of the Police Act 1997, it is an offence to obstruct a police officer during their duties, including using headlights to signal.

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The result can be a hefty fine of up to £1,000, considerably more than the minimum £100 penalty for speeding. Drivers would also get three points on their licence if caught.

Although many drivers continue to use headlight flashes as informal warnings, prosecutions do happen.

In one case from 2011, a motorist was penalised for doing just this in a case that made national headlines. The driver in the north-east of England ended up in court, and received a fine of £175, after trying to caution others about safety. Additionally, he was ordered to pay £250 in costs and handed a £15 victim surcharge.

The Highway Code has strict rules about signalling to other drivers. According to Rule 110, there's hardly ever a good time to flash your lights."

Rule 111 goes into more detail, warning: "Never assume that flashing headlights is a signal inviting you to proceed. Use your own judgement and proceed carefully."