Given the constraints of political speech-making, David Cameron's effort earlier this week was reasonable. There was the misunderstanding of international trade that one always gets from politicians when he said that developed countries were in a global race and faced a sink or swim situation. This is a common misconception. But, trade theory is tough, even for those who have the best education money can buy, so this line of reasoning is understandable. Of course, when new nations develop there are more opportunities for specialisation and trade, not fewer. The developing countries get richer and, although there may be some particular industries that suffer problems as a result of changing trading patterns, we are not in a race in some kind of zero sum game. The growth of China and India change the big picture relatively little. With good policy, our economy might grow at two to three per cent per year and with bad policy it might grow at zero to two per cent per year. Our concern should be to have good policy at home - but not because we are in some kind of economic race towards a fixed prize.

David Cameron's second error though, was rather surprising coming from somebody with a degree in PPE from Oxford. One should never be too harsh on politicians in front of a camera. It is easy to use the wrong words or for the words to come out in the wrong order. However, this was a carefully scripted speech written by professionals.

After pointing to his own educational background, Cameron said that he wanted to "spread privilege". I really hope not.

Privilege involves law that benefits the few (though, to interpret the principle more widely, the few could even be the majority). In the Soviet Union, travelling abroad was a privilege. In this country, pension contributions are "tax privileged". Doctors are privileged by laws restricting entry. An expensive education is definitely not a privilege - it is a freedom. It is a freedom that few can exercise but this does not make it a privilege.

What we definitely do not want to do is "spread privilege". Spreading privilege really means creating lots more situations where there are laws in existence for the benefit of the few. However, I am sure that is not what David Cameron intended to argue for; his intention, I am sure, was to say "widen privileges" so that existing privileges are available to more people.

But, even this is not what we should aspire to. The equivalent in the Soviet Union would be to pass a law letting some more people travel. What David Cameron really means is that he wants to "widen opportunity" or, better still, "restrain freedom less". The corporatist interpretation of his aspiration would be that he wants to ensure that education is better for everybody. The liberal (in the proper sense of the word) interpretation is that he wants to give many, many more families the freedom to choose their children's education.

Does any of this matter? Yes, it does. The meanings of words evolve, but those who believe in freedom are used to having words hijacked because it enables the enemies of freedom to make their case in an underhand way. This is why I had to put "in the proper sense of the word" in brackets after using the word "liberal". The word privilege is already used by the left in the education debate in a way that is very damaging. They argue that "higher education should be a right and not a privilege". In fact, this is using the word in the same way as David Cameron uses the word - and this is disastrous in the debate. Under new funding arrangements higher education will become a "freedom". Under old funding arrangements it was a "privilege" because laws had to be passed and regulations made that limited higher education to the few as a result of fiscal constraints (and that higher education was financed by the many for the benefit of the few). In fact, those on the liberal side of the debate are demanding that higher education should be "a freedom and not a privilege". Those on the left are actually arguing that higher education should be "a privilege and neither a freedom nor a right". The last slogan does not trip off the tongue quite as well and I am not sure the left would get much traction from using it - hence their desire to redefine words. It is the left that believe in privilege because, if access to goods and services is free, then that access has to be restricted by law creating a privileged few.

Privilege is inimical to a free society. Indeed, it is the fight against privilege that should define everything that Conservative and Liberal parties should stand for. It was a fight that began with Magna Carta. Please, let us not have a policy of spreading privilege. And please, let us also not help the left in redefining the language of freedom.

Philip Booth is Editorial and Programme Director at the Institute of Economic Affairs