The number of road traffic accidents staged by criminal gangs intent on making money from whiplash compensation has hit an all-time high, according to one of the UK’s biggest insurers.

So far this year the levels of organised fraud are already 21% higher than in the whole of 2013, according to Aviva, with more than 50% of the insurer’s fraudulent motor injury claims being made by organised gangs.

The majority involve “crash for cash” incidents, where fraudsters either deliberately crash two of their own vehicles together in private or brake sharply in front of an innocent driver’s car, causing that driver to go into the back of them. As it is the driver of the car behind that is deemed to be at fault in such collisions, fraudsters attempt to claim large sums in compensation for apparent whiplash caused by that driver. Gangs will target the vehicles most likely to have insurance and drivers least likely to cause a scene – often parents with children in the car or older drivers.

In 2013 a report from the Insurance Fraud Bureau estimated the annual cost of this type of incident to be £392m, adding around £14 to every motor insurance premium.

“Crash for cash is not just a financial problem – it’s a serious social problem. No other form of insurance fraud puts the public at risk of serious injury,” said Tom Gardiner, head of claims fraud for Aviva’s UK and Ireland general insurance business. “Last year Aviva found these accidents increased by 51%, and they are continuing to grow. Part of the growth is coming as fraudsters are moving away from a small number of hot spot locations to a much wider footprint.”

In the past the north-west – particularly Manchester – had been the focal point for the fraudulent claims but partly as a result of the number of successful prosecutions there, fraudsters have now moved on. Birmingham, Luton and north London are at the top of the list, according to Aviva.

Earlier this year the government announced that it will cut the medical assessment fees for people who claim they have suffered whiplash in England and Wales. Charges of up to £700 for an initial medical report will be reduced to £180, the justice secretary, Chris Grayling, said.

The move was part of a series of measures being looked at to reduce the number of fraudulent motor insurance claims. One of the problems with whiplash is that it can be difficult to prove whether someone is suffering from the condition or not. Under new rules insurance companies will also be urged not to accept claims without a doctor’s report showing evidence of an injury.

“Insurers recognise that crash for cash is a serious issue that impacts not just on premiums but also on the safety of innocent motorists,” a spokesman for the Association of British Insurers said. “That is one of the reasons that insurers are investing over £200m in tackling fraud.”