At the risk of starting a new thread bose-X, pilots should NEVER ident unless asked to by ATC, not that I'm saying the controller you mention was correct in his actions 'cos I don't know the exact circumstances.
Going back to AlanM's point about a 'super LARS' for the LTMA area, there was originally a plan for Swanwick to have 10 'FIR radar' positions; presumably the cost issue meant this idea had to be binned, but it does seem to me that if some sort of LARS was available everywhere under the LTMA rather than just to the east, southwest and Mig Alley, it could prevent a lot of these infringements.
I've actually already suggested a system which could be brought in using existing resources as far as possible eg piping existing radars into one unit and using spare consoles at that unit; it'll probably come to nothing; nobody ever listens to my suggestions and there's no (to my knowledge) staff suggestion scheme any more which would discuss all suggestions re their merit.