Police seizures of e-bikes across the UK have risen by 83% in a year following a crackdown on dangerous models.
New data shows 7,049 e-bikes were confiscated nationally in the 12 months to 19 May, compared with 3,858 in the previous year.
Police, politicians and charities are calling for new laws to tackle illegal bikes as a result of the figures, which have caused serious injuries and deaths in some cases.
Labour MP Julie Minns, who has been campaigning to ban sales of illegal e-bikes and conversion kits, say they were the "perfect accessory to phone theft, mugging and drug dealing" - as well as a danger to motorists and pedestrians.
Ms Minns has called for the government to designate them as an "unsafe product" that cannot be sold by online retailers.
She says illegal e-bikes do not have an MOT, are not licensed or insured, and cannot be traced as they don't have registration plates.
Out of 31 police forces across the UK who provided data, the Metropolitan Police had seized the the most e-bikes, with 2,367 confiscated in the year to 19 May.
Eleven police forces reported seizures jumping more than double year on year.
Under UK law, legal e-bikes are known as electrically assisted pedal cycles.
They must meet certain safety regulations, including having their electric motors limited to a maximum power output of 250 watts, and cutting out when they reach a speed of 15.5mph.
Non-compliant e-bikes are considered as electric mopeds or motorbikes - and must be registered, taxed and insured.
But many of these illegal e-bikes are being modified to travel much faster, exceeding 70mph in some cases.
Some modifier kits - which add an electronic motor to a conventional bike - are being sold online for under £300.
Police have begun using portable rolling road devices to test an e-bike's maximum speed using its motor to spot illegal machines, with City of London Police seizing four in half an hour last month.
Cycle team lead Sergeant Stuart Ford described illegal e-bikes as "a menace".
He said some of these are three times heavier than a conventional bike.
"If that were to hit a small child, it can cause serious injuries," he added.
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Pedestrian safety charity Living Streets has warned the "rise in e-bike use must not come at the expense of people walking".
The Royal National Institute of Blind People has also described them as "heavy, fast-moving, silent vehicles" that present a danger when "ridden carelessly".
The figures come following a string of serious incidents involving e-bikes, including a pensioner being knocked down and killed by an illegal e-bike in Sunderland in May last year and a pregnant woman being hit by an e-bike in Dorset in January, where she prematurely gave birth to a seriously ill baby after the collision.
A government spokeswoman said: "Illegal e-bikes that can reach dangerous speeds have no place on our roads and pavements, and the rise in seizures shows the scale of the problem police are dealing with."
The government has strengthened police powers so that officers no longer need to issue a warning before seizing these vehicles when they are being used for anti-social behaviour.
These powers came into force on 29 June under the Crime and Policing Act 2026.
(c) Sky News 2026: Police seizures of 'menace' illegal e-bikes jump by 83% in a year
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