probably nothing but was driving up motorway the other day car wasrunning perfect then suddenly smoke billowed through the centre console so pulled over and it was coming from the exhaust ive been told it must have been the cats burning off could it be anything more serious? if it was the cats do i need them?

You have an oil leak somewhere leaking onto the exhausts

as Dave said^^^

mine had this, possible causes would be turbo oil feeds or drains (if turbo'd of course) or back of cam covers. my VVT solanoid was leaking through the sealant dripping down the back of the engine then onto the exhaust

And, carry a fire extiguisher at ALL times!!!

so true................