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.

'It is yet another example of how criminal gangs are becoming more sophisticated and attempting to stay one step ahead of suspicion,' said Neil Thomas, director of investigative services at Asset Protection Unit (APU), a company which helps the police and the insurance industry investigate fraud.

'The adoption of flashing headlights and beckoning the driver results in a "your word against mine" situation when it comes to apportioning blame. By appearing to offer the right of way, the criminal simply continues his journey into a collision, holding the victim at fault for turning across him which, of course, cannot be denied under law.'

According to detective Inspector Dave Hindmarsh from the Metropolitan Police this type of crime costs the insurance industry a huge amount of money, with the insurance-paying motorist footing the bill.

‘The problem is a growing problem,’ he told the BBC.

‘Financially it costs insurers £392m a year. That impacts on motorists as it's an extra £50 to £100 on every person's premium, so that's a financial cost.

‘[There are] emotional costs [as] if you're involved in a crash you could well lose your confidence, and if your passengers are children they may well become wary of being passengers in cars, and of course you may get injured or killed.’ 

APU's Neil Thomas said that, while motorists should be vigilant for any suspicious activity on the road, they should, at all times, maintain their concentration on the basic rules of safe driving.