01/03/2013 12:39 GMT | Updated 01/05/2013 06:12 BST

Good Point, Prince Philip

It's not often I've felt Prince Philip's remarks have hinted at a sound political point. But last week they did.

The Prince's joke that the Philippines must be empty because half the population work for the NHS was hardly tactful, but it does highlight an important issue: a huge number of trained health professionals are leaving poor countries each year for wealthy ones. It's a massive problem: the health worker 'brain drain' is a serious threat to health improvement and poverty eradication worldwide.

The shortage of health workers is at crisis level in 57 countries; this means that for every 10,000 people there are less than 23 health workers (in the UK we have 129 health workers for every 10,000 people). As a result, these countries will not meet the health Millennium Development Goals. In particular, this means failing to prevent unnecessary deaths of children and pregnant women, and failing to treat and prevent HIV and AIDS (goals four, five and six).

Training health professionals in low-income countries costs much more (relatively) than it does in wealthy countries. It's estimated that each African health professional that leaves the continent represents a loss of $184,000 to Africa. And a huge number leave; in 2006 the World Health Organisation (WHO) estimated that 23 per cent of doctors who trained in sub-Saharan Africa are now working in high and middle income countries. That represents a massive transfer of wealth from the poor to the richer world - and it's ongoing.

If Africa is to have any chance at all of meeting the Millennium Development Goals (let alone make more ambitious progress towards genuine health equity), it will need 420,000 more physicians by 2015. But we are currently giving with one hand through aid only to take away with the other. We are creaming off workers for our own health services whose training has been paid for by some of the poorest countries in the world.

So, what can be done?

Individuals have a right to work and a right to move abroad in order to find work. That should be respected. But decision-makers in all countries also have a responsibility to consider the impact of their policies on this global crisis.

One attempted solution has been the creation of a code of practice in the UK, and subsequently (in 2010) an international WHO Code on the International Recruitment of Health Personnel. Through this WHO Code, governments agreed to stop recruiting health workers from developing countries unless there was a specific agreement in place to do so. But the Code's implementation is voluntary and has been very limited.

Due in part to the UK code, but due more to the economic downturn and restrictive immigration policies, the UK has largely stopped actively recruiting health workers from poor countries. But health workers from those countries continue to be recruited in other wealthy countries with skills gaps. And in the UK we continue to benefit from the skills of health workers who came here in earlier years, while their home countries continue to lose out on the initial investment they made in training those workers.

What is really needed is much more investment in training, recruiting and retaining health workers in developing countries. More aid? Well, yes, but we should really think of it as compensation. We owe a debt to these countries which have paid for the training of health workers, only to see them relocate (perfectly understandably) to wealthier countries where they could get better pay and conditions.

People must have the freedom to move abroad to work, and the remittances they send home to their families are an important source of income for poor countries. But this still doesn't deal with the enormous direct costs that poor countries have invested in training health workers. It simply has to change.

The UK has a key role to play. For years the UK has benefited from a free ride from some of the poorest countries in the world - siphoning off their health workers, which they have paid for and trained. Now we must pay our debts by providing resources - as compensation not aid - to strengthen health systems in the Global South, especially those facing acute shortages of trained staff. This finance should be spent on building bigger and better trained workforces, and supporting their retention through improved support and working conditions.

The Philippines, in actual fact, are not half empty. But the health systems of many developing countries do contain only a fraction of the staff they need, and that they have paid to train. It's a scandal that urgently needs to be addressed.