Interesting developments at the top of the civil service

There is to be a three-way split following the departure of the current cabinet secretary and head of the civil service, Sir Gus O'Donnell. This raises questions about lines of responsibility and the possibility of "turf wars" which I thought might be investigated at Deputy PM's Question Time in the Commons yesterday, but not one MP raised the subject. Even the quality press has been caught out. The Guardian report comes nearest to speculation of the ones I've seen.