I've got a Mk2 Focus 1.8 TDCi which gives a large blue smoke cloud when started from being completely cold. It usually starts ok without any excessive cranking but runs lumpy for a minute or 2 if driven straight away. After running for a few minutes it's absolutely fine.
The smoke only occurs when the car has been stood overnight. The colder it is the more smoke there is. The engine has done 50k and isn't using any oil.
Could it be the glow plugs ?