Interviewed by The Guardian, new health secretary Andy Burnham has suggested that prevention of lifestyle-associated ill-health will be a personal priority.

Burnham sees the British population getting on their bikes not to look for work (as Norman Tebbit's father reportedly did), but to ward off the impending crises in obesity and diabetes through exercise. He is reported to view expenditure of public money on fitness and prevention as "a long-term insurance policy".

Green light for get up and go
Burnham tells Sarah Boseley, "I want to signal from day one a very big and large green light to every primary care trust in the country that it's not a risky or a frowned-upon thing to start putting money into physical activity promotion … There has been a sense I think out there that it's a little bit of a sideline, but the time has come to really attack that much more aggressively." He fully endorses the Change4Life campaign initiated under his predecessor Alan Johnson.

It's easy to be cynical about this, especially when a long incumbent party is facing tough electoral prospects. Burnham's statement that the long pay-off time for upstream investment in health is discouraging in government is a mere statement of political fact.

For all that, a cautious two cheers should certainly be raised. The tail-end batsman in cricket has an important role; the tail-end ministers of a government staring down the barrel of electoral unpopularity no less so.

Labour remains in office. It remains to be seen whether the Brown reshuffle will keep him and his ministers in power, or whether the civil service simply give up and play inertia. They have the power to dictate the agenda for a few months yet.

What do PCTs stop spending on to fund this?
The caveats are mostly obvious. What should PCTs disinvest in funding to put money into this scheme? There is no extra largesse available from Treasury coffers. Burnham is silent on the subject, and The Guardian does not seem to have asked. Nor is it clear how the funding can be maintained in 2010-11, when funding growth of the NHS will almost certainly all but stop dead.

There is also a risk of widening health inequalities. A badly-designed scheme could start to subsidise the leisure habits of people who could afford to fund their own leisure or sport activities. What is the data on the groups most at risk from lifestyle illness, and how will such a scheme target the resources on the people who will benefit most? This does not mean that a well-designed scheme is not worth trying: there may be good results in social solidarity if the scheme can attract providers such as fitness clubs and gyms that have been beyond the reach of lower socio-economic groups, and who are afflicted by post-affluenzea belt-tightening of the mega-mortgaged classes.

Finally, there is a point to be made about people's attitudes to what Burnham compares to "long-term insurance". The most obvious form of long-term insurance is pension savings, which are in a parlous state. Mr Brown's raid on pension schemes as Chancellor, and the vicissitudes of the stock market, have not encouraged people. The attractive appreciation in property prices has sung a siren song.

The right thing to do: handle with care
It is probably right to make an intellectual case for spending on upstream measures in those terms. However, making a popular and electoral case may have a better chance if it can be presented as a positive and enabling activity to enjoy a better quality of life. Prudence may no longer be the name-check of choice in a time of quantitative easing, but to manage the public's perception of 'the man from the Pru'-style, jam-tomorrow politics of this proposal - even though it is the right thing to do - will be no small challenge for Mr Burnham.

Let us wish him luck. He needs it.