Children as young as eight have been caught stealing vehicles in Lancashire – with almost half of motor thieves under 18.
Almost 2,500 youths have been detected stealing cars, motorbikes and even construction vehicles in the past five years.
The youngest thief was an eight-year-old who stole a dumper truck in Chorley.
He could not be charged as he was two years below the minimum age for a criminal prosecution.
Other offenders included a 10-year-old who stole a motorcycle in Preston and an 11-year-old who took a Ford Transit van from Carnforth, near Lancaster.
Both were let go with a caution.
Police caught 1,075 people stealing vehicles in the county last year – 495 of whom were youths under 18. Less than half of those, 215, were charged by police.
The Lancashire Evening Post uncovered the figures following a Freedom of Information request to Lancashire Police.
Ribble Valley MP Nigel Evans branded the statistics "alarming" and called for authorities and parents to do more to tackle the problem.
He said: "Eight-year-olds should be playing with Corgi cars, not stealing real cars.
"They have got to be properly dealt with to nip this in the bud.
"And parents need to learn to be responsible for their own children."
The numbers of youths detected increased from 391 in 2005/6 to 495 last year, but is down from a peak of 561 in 2003/4.
Det Insp Ian Dawson, of Lancashire Police, said it tended to be teenagers rather than primary school children involved in car crime.
He added the force was working with schools and the car thieves to educate youngsters about the dangers of joyriding.
He said: "They tend to take cars to use them for their own enjoyment but they are not able to control these vehicles, let alone drive.
"There is a knock-on effect – these vehicles can be crashed, abandoned or damaged.
"We want to stop offending by giving them an education – if they see taking a car as fun, we want to educate them why it's not."
Andrew Howard, head of road safety at motoring organisation The AA, said unlicenced drivers posed a serious danger to pedestrians and other motorists.
He said: "A lot of the time, it's a thrill-seeking crime.
"It's not just the fact these people don't know how to drive but the fact they steal cars to show off.
"A large number get set on fire once they've gone for a spin, which creates a considerable problem for the fire brigade."
Police in Fishwick warned of a "gang culture" among young joyriders on the Callon estate five years ago.
John Paul Newsham, then 16, was banned from parts of Callon under a two-year ASBO in 2003 after being caught driving around the estate on at least 17 different occasions.
He used vehicles with no registered owners and also had a conviction for stealing a car.
>> Vote in our latest web poll