If there is not enough medicine to go round, who should be first in line - and who should decide? 

Unusually, we have advance warning of an influenza pandemic. And we have some tools to head it off. But the UK alone has 60 million people to protect - almost certainly there is not going to be enough oseltamivir or flu vaccine to go round. A stockpile of 14.6 million courses of anti-viral drugs is being built up. This would be most effective if used prophylatically - to prevent people becoming infected. But who would get it?

Some suitable causes are hard to disagree with - people involved in drug/vaccine manufacture for starters, as well 'frontline' healthcare workers. But who else? Are our politicians deserving causes? Civil servants? Teachers? The Royal Family?

One academic paper in 2006 suggested that, with limited vaccine supplies, a simple 'save the most lives' equation is not necessarily the best strategy. A better approach would be to maximise the number of years of life saved, and to take account of the 'investment' in life to date. Crudely put, that means prioritising people from late childhood to middle age.

This may seem distasteful, and the authors acknowledge they are proposing 'the least bad solution to a tragic situation'. But some decisions of this kind may have to be made.

So who would make these decisions? Nancy Kass, an ethicist at Johns Hopkins University, has argued that lay heroes - the unsung individuals on whom society depends, such as truck drivers and refuse collectors - should be included; without them, society may not function.

And, she argues, 'ordinary people' should also be involved in discussions about priorities. Partly this is to ensure fairness, but also to create a sense of transparency and buy in - why should people agree to plans that they have had no chance to influence?