Insurance giant Aviva says it has more than 17,000 suspicious whiplash claims under investigation.

The firm, which increased its profit before tax from £496m to £562m in 2015, has published figures purporting to show a ‘gravy train’ of fraudsters making spurious claims.

Aviva said it detected more than 3,000 organised so-called ‘crash for cash’ claimants in 2015, with one in every four claims occurring in Birmingham.

But the number of induced accidents, where drivers deliberately target innocent motorists to claim whiplash compensation, in fact dropped by 2% compared with the figure recorded in 2014.

And the number of ‘staged’ accidents, when two damaged cars are brought together to make it appear like an accident, and bogus accidents detected by Aviva fell by 40%.

The whiplash debate has intensified in recent months, with the announcement last November by chancellor George Osborne that he intends to ban general damages for soft-tissue injuries. The Ministry of Justice is due to publish a consultation on the matter this year.

Aviva said detected motor fraud has a value of £58m, with one in nine whiplash claims ‘tainted’ by fraud. Around 4,000 motor injury claims under investigation are thought to be linked to known fraud rings.

Tom Gardiner, head of fraud for Aviva, said: ‘We remain very concerned that fraudsters continue to put their own greed ahead of innocent motorists’ safety. Our figures show induced accidents now account for nearly half of all organised motor fraud we detect.

‘Crash for cash does not just push up premiums for genuine customers, it puts innocent motorists at risk. It is also a significant drain on scarce public resources such as ambulance, police and A&E time, all of which are wasted on these entirely bogus claims. The number of whiplash claims is a problem unique to the UK and needs urgent reform.’

Birmingham, north London and east London are named as the most common areas for induced accidents in 2015, with Leeds and Harrow making up the top five.