The last thing I want is to become known as is one of those idiots who hates on experts. Like a lot of people, l work in a specialised field that requires a lot of training and in which a little knowledge can be a dangerous thing. Expertise and proficiency is salutary and is at the heart of an advanced society.

When it comes to the public square, however, there is a necessary limitation on just how much power experts should be yielded to experts. This is partly due to democratic concerns. However, it is also the case that "civillian" officials are sometimes in a better position to make more rounded decisions.

There is a good (and very literal) example of this from the annals of World War One. During what is sometimes called the First Battle of the Atlantic, German submarine warfare had Britain on the ropes. To combat this, the government wanted the Royal Navy to revive the system of naval convoys, by which merchant and troop ships would travel together protected by escorts.

The Navy brass did not want a bar of this. The admirals refused, resisted and delayed the adoption of convoys. In their expert view, travelling together like that would make shipping an even more inviting u-boat target. Furthermore, the practice would violate the then expert consensus that defensive strategies were doomed to fail and that the only way to win any conflict was to go on the offensive.

David Lloyd-George persisted, however, and even had the First Sea Lord (a noted opponent of the convoy system) removed from office.

In the event, convoys proved very effective and British losses declined dramatically. The effect of convoys is widely credited with the British victory in the Atlantic. And the war itself, some people say.

None of this is to say that politicians are always right and experts are always wrong. That would be a foolish thing to say. Experts are recognised as experts because they have so much more knowledge in their field than lay people do.

But it does illustrate a couple of hey points. First, it is entirely possible for an expert class to become locked into dogmas that blinds them to common sense possibilities. Second, it is equally possible that responsible politicians can make a good call that contradicts the expert advice. Of course, they carry the can for any subsequent failure which is why, ultimately, it should be their call and it is good that our system assumes that this will be the case.

Expert advice is always valuable but, ultimately, it is advice, not instruction. Any politician who wants a legacy as a leader must, from time to time, be willing to back their own judgment.