But if all he does is send a loud and clear signal to the civil service, he will have done something necessary but not sufficient. Deeply embedded perceptions created by overdoses of Yes Minister re-runs notwithstanding, civil servants do on the whole respond (sometimes slowly, sometimes imperfectly) to the signals they get from ministers. That works even more strongly the other way: in the absence of clear signals, they won't respond. And one of the core skills of the most senior civil servants - one of the reasons why they are the most senior civil servants - is a finely tuned ability to distinguish between what ministers say when the only real intention is to have said something and what ministers say when they have a concrete desire for something to be different as a result. Following TBL's precepts won't be easy and will have costs and opportunity costs. Unless those officials hear consistently from ministers that they want this to happen and are comfortable with the consequences of its happening, it won't happen.