Dubbed “flash for cash”, the scam is a variation on the well-known “crash for cash” crime in which criminals brake suddenly for no reason, forcing the victim to crash into the back of them. In both scams, the perpetrators then make fraudulent insurance claims, including for fake whiplash claims as well as loss of earnings and fake bills for vehicle storage, recovery, repairs and replacement car hire.

However, "flash-for-cash" is said to be harder to prove in court, often just pitting the innocent driver's word against the criminal's that they flashed their lights to let them out.

In response IAM training manager Simon Elstow has the following advice:

How to avoid them:

• Always look ahead and anticipate hazards, so you aren’t ‘cornered’ into a crash you can’t avoid.
• If someone flashes you to invite you out of a junction, thank them but don’t go – wait until the road is clear for you to progress. 

If you are involved in one, remember:

• If you’re suspicious, don’t ask them directly about it at the scene but keep careful notes.
• Try to take photos of the damage to all vehicles, discreetly if possible.
• Get a description of the driver and count the number of people in the other vehicle. Take photos, discreetly if possible, of all the people in the vehicle.
• If you need the emergency services, call 999, and if you are suspicious about the incident, tell the police when you ring.
• Stay calm. You’ll need to swap details with other drivers whatever happens.

Elstow said: ‘”Flash-for-cash” scams are costing millions of pounds through our insurance premiums, and some are so reckless that they risk lives. Collisions are stressful and emotionally draining, but it’s important to be prepared in case you are involved in one.’

‘Make sure you drive carefully to minimise your chances of having to deal with a collision.’