Some taxes encourage actions that lead to good consequences: Gift Aid, for example, exists to encourage charitable giving.  Other taxes discourage actions that can lead to bad ones.  Alcohol can brighten up a man’s evening but it can also destroy his life, sometimes literally, and devastate the life of his family.  Hence beer duty and cider duty and wine duty and spirit duty, all set to strength.  So it is that beer with a strength between 1.2 per cent and 1.8 per cent is taxed at 8.1p per litre and that with a strength of 7.5 per cent is taxed at more than 23.8p per litre – and so on.  Taxation is the nudge principle made flesh, or can be.

That setting a tax too high can encourage a black market – see cigarette duties – or that government has other instruments to hand than taxation, such as advertising or regulation, is beside the point: namely, that this is a sensible way to use the tax system, which is required to raise the revenues to fund the public services which all of us other than those lost in the libertarian void acknowledge we need.

It follows that there is no reason in principle not to target the consumption of sugar with a specific tax – since sugar, like alcohol, can be bad for your health.  Practice, of course, is not the same as principle, and so it is in this case.  A new sugar tax would hit poorer people heavily.  It could have dire political consequences.  It would be a significant new measure – and not, therefore, one that should be introduced without a manifesto commitment.  In any event, there are alternative means of persuading people to consume less sugar or take more exercise or both, which takes one back to the point about advertising (or labelling).  David Cameron is smart to side-step Public Health England’s report.

Given the objections to a sugar tax in practice why, then, stress that there are none in principle?  Because it is important for the Centre-Right to think more clearly and creatively about the role of the state than it sometimes does.  Most Conservatives, including ConservativeHome, want the state to be smaller.  But this is not to be confused with wanting it not to exist at all, or seeing it as an enemy.

The state provides a service that nearly Tories admire if not revere, the armed forces, and has a head who evokes the same response – the Queen.  But Britain is more than a market with a flag, or rather the Queen, on top.  Even were the state to provide fewer services itself – schools, hospitals, roads, policing – it would be responsible, in our modern world, for ensuring that others did so.  It is, in that atrocious but unavoidable word, an enabler.  Most voters may not use the term, but they rub along with what it means none the less.  Argument about whether it is too big or too small – or shouldn’t be there at all – is largely confined to politicians, members of political parties and political enthusiasts.

If you doubt it, ask yourself how many people you know – outside these restricted circles – have ever said to you: “Do you know what…I think the state is too big?”  (Or “too small”, for that matter.)  Yes, me too. Scarcely one.  This is the language we punt about every day on this website.  It is not that used by the mass of people who snuggle down each Saturday with Strictly Come Dancing or the X-Factor.

Or, to be more accurate, are watching TV shows in declining numbers, and doing other things.  They complain about government getting it wrong, but expect it to be there.  They view it less as a friend or an enemy than a fact of life.  This is not only a wise view but a suggestive one.  The Conservative Party needs more votes.  One way of winning them is to hold it.