Your car won't pass an MOT as it is illegal to de cat cars registered after 93 in the UK.

Check the CTS first as said, the info recieved from this sensor is used to control the base level of fuel injected right from freezing to boiling, being it's essentially a thermister they do go out of calibration.

I think you should also make sure your C/L is working ok as well, having the cat would make alot of differance to the emissons.

Martin