Based on the attention the government is devoting to the issue, you could be forgiven for believing that "health tourism" is a significant problem. Ahead of his speech on the subject on Wednesday, Jeremy Hunt has vowed to end the "costly abuse" of the NHS by foreigners, declaring that "by looking at the scale of the problem and at where and how improvements can be made we will help ensure the NHS remains sustainable for many years to come". In the speech, Hunt will announce plans to introduce a new tracking system linking a patient's NHS number to their immigration status and GP charges for those not entitled to free care. But how "costly" is this "abuse"?

In 2011-12, the NHS officially spent £33m on treating foreign nationals, £21m of which was recovered. This means that just £12m, or 0.01 per cent of the health service's £109bn annual budget, was lost to "health tourists". In March, when David Cameron raised the issue in his speech on immigration, Hunt claimed the true figure was £200m but produced no evidence to support his claim. But even if we accept the Health Secretary's estimate, this figure accounts for just 0.18 per cent of the NHS budget and that's before we take into account the savings made from British nationals using foreign health services and the administrative cost of the new "crackdown".

As ever when immigration is discussed, it's also important to remember that migrants contribute far more in taxes than they receive in benefits and services. An OECD study earlier this month found that they make a net contribution of 1.02 per cent of GDP or £16.3bn to the UK, largely because they are younger and more economically active than the population in general. As I've noted before, if David Cameron wants to reduce the national debt (and he hasn't had much luck so far), he needs more immigrants, not fewer. While zero net migration would cause the national debt to rise to more than 160 per cent of GDP by 2060-61, an open-door approach would see it fall to around 40 per cent from its current level of 75.2 per cent.