A Gordon Brown-led government offers new possibilities for food policy but whether he will take the issues seriously remains to be seen

Tony Blair's departure has been painfully slow and the arrival of a Gordon Brown-led government offers interesting possibilities. Brown now faces a balancing act. On the one hand there is his (presumed) loyalty to his own decade of central involvement in Blair's leadership. At the same time, he has to suggest something different - whether in tone or substance remains to be seen. Meanwhile, the vast majority of people yearn for change.

Brown cultivated his fiscally dour and controlling reputation when it suited, but he likes a well orchestrated surprise. Remember, he sprung Bank of England independence. So what three things might surprise me on food policy?

Firstly, I'd be stunned if he reversed the love affair with big retailers. 'Leave it to Tesco' is an unwritten New Labour policy rule. The role of big retailers as the champions of lean Toyota management is unlikely to shift.

But Brown believes in competition. He could just broaden the remit of the Competition Commission to include more local, social and environmental impacts. It would be too late to affect the current supermarket inquiry, but would be important nonetheless.

Secondly, I would pass out with excitement if he demanded a serious shift to preventative health measures. He's the chancellor who funded not one, but two reports on the long-term cost horizons of NHS healthcare.

These showed that prevention, not least through diet, on a population-wide basis is cheaper than the current drift. Health education has limited effect. Prevention is a good investment. and passes the Brown "prudence" test. He may look at inequalities in health as targets for government action.

Thirdly, it would be wonderful if he took a lead in steering not just farming but the entire food chain in a more ecological direction.

E.coli led to the FSA. And foot & mouth disease led to the abolition of MAFF and the Curry Commission. Brown has run the Treasury when it's rightly lost patience with farming's endless call for funds from the Exchequer in crises.

However, Brown is also becoming prime minister in the era when climate change is a top priority. Costing carbon to raise - yes raise - the prices of energy-dense foods would shift diets.

I have been at two conferences in the past month where the enormity of this was discussed. Carbon, like fat, is too cheap. The food supply chain is waking up to that. Will Brown take it seriously, too?

Tim Lang is Professor of Food

Policy at City University, London