This story has done the rounds before, about a month ago. I think it's dangerous talk. Firstly, it gives an impression that the politicians have a core role in departmental business. Is holding on to one politician really going to have an effect on MoD operations? Come off it.
Second, what happens when we have a general election? Are the Chiefs going to ask to keep Gordon as PM so they can continue planning for Iraq and Afghanistan? No, don't be silly.
It's the PM's decision who he shuffles, not a department's. Anyway, do the Chiefs really want to keep hold of a part-timer?