Where does it say this? I spent ages yesterday googling and couldnt find anything. I even found forums where other people had done the same and not managed to find anything. I know its a legal requirement that all cars built after 1993 have to have a cat fitted when they are made. But, couldnt find anything saying that its illegal to drive a car without a cat fitted.
Not doubting you, but would be good to have concrete evidence to settle this debate.
let me get home from work, and i shall email the VOSA for a definitive answer, and i shall post up the reply when it comes,
logic would dictate that if its a legal requirement for them to be built with, and you need one to pass your MOT, and that by swapping them out at MOT means that your car isn't actually road worthy. which means your insurance policy isn't actually valid. would make me think they aren't legal.
but if you want to hear it from the VOSA themselves i'll write it tonight