Why fine someone £6000 for busting airspace? What they should do is to order some retraining with a CAA inspector / examiner and invalidate their licence until it has been completed. If they fly with an invalid licence, then fine them £6000.
Surely it depends on the circumstances and the effects of their infringement ? If we knew that, then we could all make our own judgement on the scale of the fine and whether it was a suitable way of dealing with the matter. It does seem high to me, compared to other fines you read about for other criminal offences.
Perhaps a nominal fine closer in value to those motorists might have to pay, plus the pilot paying the costs resulting from their actions might be more effective. These costs might rightly include those incurred by commercial operators having to break off their approaches
How much ?? Well, here's the CAA poster
Flyontrack Infringements Poster
Generally speaking, most ATC units, although having to take reporting action, will not be thinking of a CAA prosecution as the next step UNLESS safety has been compromised and/or there has been disruption to the flow of air traffic.
Mostly they will seek to talk with the pilot, find out what happened, and offer guidance on what to do to prevent a reoccurence. If the pilot is receptive and the two way exchange of information resolves things to the satisfaction of both, then the report is closed from the ATC point of view without recourse to CA939 action (Breach of Legislation). Filing the report will however help identify trends, both in individuals and pieces of airspace. I guess if a particular pilot makes several low impact busts and doesn't appear to be 'learning' then the CAA might be asked to get involved.