Man of Honour
Well I don't think that Karl is a scripted character at all.
Go back to the very first XFM shows where he was ocassionally asked stuff and he gave stupid replies which were very genuine.
When Merchant & Gervais heard some of this garbage they knew they had got a little goldmine in their company and as the show progressed the character of Karl progressed into total stupidity.
It's obvious that some of the sketches were (not scripted) but talked out about before the show aired.
There are lots of other stuff where it was obvious he hadn't thought of that one liner on the spot because they were genius.
The Idiot Abroad series had some great camera angles to get jokes over which were supposed to be 'off the cuff'.
One such scene is him eating Monster Munch sitting on the pavement while his driver ate some live insects, cameras are panning back and forward in perfect time for the scene which wouldn't happen if he just made it up on the spot.
OR he did make it up on the spot and the producer decided to make a scene around it so what we see is not exactly how it happened.
This is how great comedy works.
I just have a problem with people who think he is genuinely thick and yes, go back on this forum and you will see posters who genuinely believe that they think Karl believes the Monkey News scripts.
The guy is a genius and I'm a massive fan.