Adrian Chiles investigates the extraordinary rise of electric bikes on our streets and what that means for drivers, pedestrians and cyclists. He asks whether, despite their green credentials, they are a solution to our congested towns and cities or a new menace in need of tighter regulation. He discovers that some more powerful and faster e-bikes, while openly sold as commuter bikes, are illegal to ride on the road. Sales of e-bikes have boomed but, as they are crammed into the same space as pedestrians and other road users, councils and the police are struggling to cope with the e-bike revolution.