Cheerful Andrew Lansley sounds like a man who believes that the end of his long trek towards ministerial office is finally in sight. He is probably right. By the time he becomes what we must start thinking of as secretary of state for public health he will have shadowed the job for almost six years.

An arduous apprenticeship and Lansley’s conversation is peppered with facts, figures and authentic enthusiasm. He also has spare energy to take me to task for questioning some of the assumptions behind A Healthier Nation, his new public health green paper.

The green paper is awash with bright ideas, based on the “nudge” theory of social psychologists

If the Tory draft health manifesto had three core points (a patient-oriented, outcome-driven NHS; greater localism and accountability; and improving the health of the British people) the core of the green paper seems to be protecting a locally driven public health budget.

As finance directors know better than most, that is where hard pressed primary care trusts often look first to find cuts; there are no obvious victims waiting in accident and emergency or for an op, are there? No.

Lansley plans to split the NHS budget between NHS services and public health. What ratio? He won’t say, but draws attention to Health England’s calculation that public health currently gets 4 per cent.

The “health premium” concept that so enraged health secretary Andy Burnham in last week’s HSJ would be based purely on the relative burden of disease in poorer areas - on actual health outcomes, if I have this bit right - not weighted by extraneous factors as it is under Labour, he insists.

It will be fairer, though not always in ways you might expect. There is one bed per 245 people in the North East, one per 408 in South Central, he notes in passing. Hmm. But much of his thinking is based on recommendations of the non-party Public Health Commission.

As with many policies outlined by a government in waiting, much must be taken on trust in an untrusting age. The Tories have scaled down some commitments, on single beds for instance (sensible: it is expensive) and the precise functions of the new NHS executive board.

Last week’s emphasis was on the re-integration of the Health Protection Agency and parts of the Food Standards Agency into a department with far greater public health functions. As with climate change policy much of that focus will be on changing behaviour - the lifestyle choices involving food, drugs, sex and exercise - and demand rather than supply.

Such talk brings Lansley into collision with the health select committee’s new demand for a 50p a unit price of alcohol - a classic supply led response I supported here. So does Burnham, although Gordon Brown does not (it is a big dispute in Scotland), Lansley points out with glee.

The Conservative line is that such a policy hurts the respectable poor too much. Better to focus on specifics, cut-price supermarket offers (to be banned), cheap, strong lager, white cider and, I suppose, red Buckie, the Devon monks’ tipple (15 per cent proof) beloved of Scots boozers.

Fine, fine. The green paper is awash with bright ideas, based on the “nudge” theory of social psychologists, policies which steer people towards changed behaviour rather than instruct them. How? Giving people cheap gym deals so long as they actually turn up; telling voters - students for instance - just how much the average student actually drinks (less than you might think).

We want new ideas. Labour has been short termist, abandoning some public health schemes too quickly. But talk of “discussing” and “encouraging” the food and drinks industries to do better makes me think we’ve been here before.