But not legal as a bike.Yes, legal under EU rules since there have also been some compressed air powered cars running on the road in France that more than one company has long been promoting. They have zero road tax too as ultra low emission vehicles.
Peugeot's is a hybrid, but the first company promoting this had a pure pre-compressed tank city car.
.
It has only one brake!
And the exemption to be classed as a bike is only for electric bikes not any other type of engine.
So it would need to reach moped MOT standards as a minimum.