Teenagers are brazenly boasting about motorcycle thefts and mocking their victims on TikTok.
A BBC investigation has found hundreds of videos showing self-confessed thieves posing with stolen bikes. In some cases, social media is being used to sell them.
Victims say they feel helpless seeing their prized possessions paraded like trophies online.
Figures show that, where age was recorded, more than half of all suspects for motorcycle thefts in Great Britain last year were under the age of 18.
One crime expert describes the thefts as "a game" in which teenagers compete with one another.
TikTok says it has removed some accounts for breaking its rules. However, the BBC has found hundreds more videos remain live on the platform.
Richard Thompson says his wife was working a night shift as a carer in Grimsby when her moped was stolen.
He has a CCTV image of the bike being ridden by three masked young people and believes one is aged between 10 and 12.
The BBC found a video of his stolen bike on TikTok, posted with the caption: "Catch me in traffic #stolen".
Thompson describes the video as "disgusting".
"How much more proof do you need?" he asks. "Ban these accounts, because they are brazenly showing stolen property."
After reporting the theft to Humberside Police, Thompson says he used social media to try to trace the bike. He was told about potential sightings and given the names of suspects.
He says he contacted a parent of one of those thought to be involved, who confirmed it was their son on the bike in the video.
Thompson says he was angered by the police's response and believes the teenagers must "feel untouchable".
"The policeman said to me: 'What do you expect us to do, because if we see them on the bike we can't chase them? If they fall off they could hurt themselves'," he says.
"My response was, 'wow, I'd expect you to do your job'."
His case was opened on 27 October 2025 and closed two days later.
A spokesperson for the force says officers reviewed videos and images from social media, but they provided insufficient evidence to identify those involved.
Officers also visited an address linked with the bike, but the evidence was not strong enough to enable a search.
The TikTok videos found by the BBC were posted under a series of hashtags that appear to celebrate theft.
In the clips, the faces of self-confessed thieves are covered with balaclavas or emojis. Some pose with bolt cutters and others offer advice on hot-wiring vehicles.
The BBC examined the accounts of two individuals claiming to be motorbike thieves. Each has more than 1,500 followers and their posts have been liked thousands of times. Some of the videos date back to 2023.
On one TikTok account, which the BBC is not naming, a victim is openly mocked for pleading for help to find their stolen possessions.
The BBC sent freedom of information requests to 45 UK police forces. Of the 31 comparable responses received, there were 9,581 recorded offences of a motorbike being stolen. Police only recorded an age for 1,812 suspects. Of these, 965, or 53%, were under the age of 18.
In comparison, across all crime in England and Wales in the most recent year of data, only 8% of arrests were of people under 18.
Dr Ken German, of the UK's Motorcycle Crime Reduction Group, advises the government and industry.
"It's all a game," he says of the teenage thieves.
"They want to do it in the quickest time, they want to wave and take pictures of themselves, which is why they're on TikTok.
"They know that they can make one or two hundred pounds, but in essence they are playing with each other and competing with each other."
Kenny Wilson, from County Durham, runs the Bikers against Bike Theft UK campaign group.
He says frustrations are running high and, despite strongly advising bike owners not to take a vigilante approach, fears some will "snap and say enough's enough".
He describes being told of one potential vigilante response when a man reportedly had his fingers "severely damaged" after stolen motorbikes were found in his back garden.
The BBC understands an 18-year-old man, who was questioned by police about stolen bikes in North Yorkshire, had to have treatment in hospital for hand injuries. Two men were arrested on suspicion of assault.
Thieves stole two motorcycles and attempted to take a third from the driveway of Sam Gibb's home in Grimsby in September 2025.
One of the bikes – her son's "pride and joy" – was worth more than £6,000.
"His whole life is that bike," says Gibb. "It still had over £3,000 of outstanding finance left to pay on it."
She is one of several victims who say they have carried out their own investigations.
"We aren't getting help. They are just running amok," she says. "The police weren't doing the investigating."
Gibb discovered her son's bike had been sold for £300 on Snapchat.
"He's still got a £3,000 bill and they've sold it for 10 times less than that."
Humberside Police says a 17-year-old boy was not charged in connection with the case, but did go through a youth justice process, which can involve a warning or caution.
Snapchat has not responded to a request for comment.
Humberside Police is increasing resources to deal with motorcycle crime and has recruited four full-time officers in northern Lincolnshire.
They are armed with drones with thermal capabilities to track vehicles at speed and spot hidden bikes.
All 21 arrests relating to motorcycle theft in Grimsby in 2025 involved teenagers aged 18 or under.
Insp Pete Musgrave says he is aware of social media being used to "glorify" thefts and understands the frustration of victims.
He is urging people to pass on information to police.
"Whether they're an 11 or 12-year-old on a bike, or they're a 25-year-old on a bike, we will deal with them," he adds.
The National Police Chiefs' Council says a crackdown in October 2025, called Operation Alliances, resulted in more than 580 arrests, the recovery of about £4m of stolen vehicles, 260 property searches and the uncovering of illegal chop shops.
A spokesperson says forces "are making strides in tackling the offenders", but the "ultimate goal" is prevention.
Ofcom says social media platforms "must assess and mitigate the risk of UK users encountering criminal content" and it will "make sure sites and apps are taking appropriate steps to do this".
TikTok says it has removed some user accounts and "taken action" against search terms violating its community guidelines.
The company says it "proactively removes" videos for violating its policies on "violent or criminal behaviour" before they are reported to the platform.
Data journalism by Alice Evans and Jonathan Fagg.
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