Removal of a catayltic converter where one was fitted originally is clearly illegal and in contravention of the Construction and Use Regulations because it is a modification which will affect the exhaust emissions. The difference is whether the presence of the cat is part of the MoT test procedure or not. I don't believe it is at present but don't mention it or that will be another loophole sealed off.
(EDIT: I checked the VOSA manual and yes you DO have to have a catalytic converter fitted if one was supplied as original equipment. Doesn't matter if the emissions are within the standard, the converter has to be physically present.)
If they are as determined as Ned suggests to stamp out DPF removal, then there is no long-term hiding place.
Last edited by 97396; 06-12-13 at 16:42.