The law that governs the speed limits on our roads is actually The Road Traffic Regulation Act 1984 Part VI (Speed Limits), in which the wording specifically says that the limits are for “motor vehicles.” This means that pedal bicycles have no speed limits on UK roads. There’s a chance e-bikes would have been classed as a motor vehicle, but as their motors are required to turn off at 15.5mph by another piece of legislation the point is pretty academic.