An investigation found that Amazon sells Chinese conversion kits costing under £500 that can turn ordinary bicycles into e-bikes capable of speeds far above the UK legal limit. Although selling the kits is not currently illegal, the findings have intensified calls for tighter controls as police report more seizures, accidents and crimes involving modified e-bikes.

UK e-bikes are limited to a 250-watt motor and assistance up to 15.5mph; faster or more powerful machines must be registered, taxed and insured as mopeds or motorcycles. The investigation fitted a 500-watt kit to a second-hand bicycle for about £700 in total, producing speeds above 25mph, while online retailers advertise kits of up to 5,000 watts and devices that remove speed limiters. Police seizures rose 83 per cent to 7,049 in the year to 19 May, and campaigners cite links to muggings, drug dealing and fatal collisions.