It seems rather stupid to me that unbraked trailers must have a secondary coupling but braked trailers must have a cable to apply the brakes.
For an unbraked trailer the secondary coupling must keep the nose of the trailer off the ground and still attached to the vehicle - fair enough!!! What seems truly bizarre is that a braked trailer must be allowed to detach itself and apply the brakes!!!
It would seem to me far more sensible to use a secondary coupling on ANY trailer - in fact I always do so but I wonder if I were to do so on a braked trailer and had an accident if I would be punished as that is not what the law requires?
Also didn't realise there was no legal requirement for the weight of the vehicle/trailer to be matched.