Anyone know how the UK law operates regarding pusher type trailers ? I'm thinking of one which would attach closely to bike in such a way that it's look like "stabilisers". I was thinking of building a trike and debated over making rear axle, linking pedal and electric power to the axle etc. The idea developed into one which I've seen for motorbikes ( http://www.tow-pacinc.com/ ) - a horseshoe shaped frame that loops around the back wheel leaving it in situ. The additional, powered, wheels attach to this frame that also carried batteries. Although rigid in horizontal plane still allowed to move vertical and kept in contact with road by weight of batteries. The "horseshoe" would be attached to bike by quick release pins so easilly dismantled for storage, carrying or allowing bike to be used unassisted. My opinion is that the 60 kg / 250w law would apply.