Diplomats are expert at couching hard truths in soft language, a trick that leads to ambiguity. There's not much of either in the letter Sir Ivan Rogers left for his staff when he left his post several months early so that he was no longer there when negotiations for the UK to leave the EU start in earnest. In Whitehall, this morning, there will be more bloody noses than pulled punches - but Whitehall has a treacle-like approach to criticism. Standard operating procedure is to hang-around until the fuss dies down, then carry on as before.