Freedom of expression and censorship are fast becoming the most used and misused terms in public forums, the press and on the internet. A number of people, ranging from the learned to the downright ignorant, are using them to suit their own ends despite having little or no idea what they actually mean.

'Censorship' should be simple enough because it is clearly defined in the dictionary. It is either applied to suppression on the grounds of obscenity or national security, or making deletions or changes with some ulterior motive in mind. It should not be confused with 'editing' - which means, among other things, to choose, refuse or modify someone else's material for the purpose of publication in a particular medium which may be limited by space as well as having its own style and character - yet it often is.

Freedom of expression is a lot more complicated. However, it is clear to most people from the outset that it is not an absolute right. It certainly cannot be taken to mean, for example - as it has been in the case of the University publication case - that it is the freedom to say or write whatever one wishes irrespective of legislation. That kind of liberty can only truly exist in the privacy of one's own home, and sometimes only in one's own company. In most countries it is lawful to speak out on condition that this is done in such a way that does not unduly offend others, or put them at risk in any way.

PBS is defending its decision to invite Norman Lowell as the only guest on a live prime time television programme on the grounds of freedom of expression. The national station maintains that the public has a right to see an "extremist" of this nature and that journalists have a right and duty to expose unpalatable truths about people like him.

This argument can go some distance. There is no doubt that an important function of journalism is to inform the public about a number of things they might not otherwise be exposed to, and that condemning or preventing any such an opportunity should only be reserved, as the programme presenter himself said, for "extreme circumstances".

However, by the state broadcaster's own definition the person interviewed was an "extreme" circumstance. He has been convicted of racial hatred, refers to the six million Jews who died in the Holocaust as "ghosts", believes disabled people should be aborted or euthanised, and says those who adopt African children should enjoy them in their "natural habitats".

These notions - which are less original than old socks and as edifying as herpes - put forward by a dark-skinned member of the Maltese community in a version of Maltese that is anything but pure, may be laughed at by the majority of people, as Hitler was when he first advanced such theories while he was living as a failed painter with tramps in a German doss house.

But there is the obvious danger that by putting such a person in the same chair and in front of the same audience as our Prime Minister and Leader of the Opposition, he is being somehow legitimised, and can therefore increase his support base.

Despite being bashed by all around him, the UK Far Right leader, Nick Griffin, described his controversial appearance as one of the panellists on the BBC's Question Time programme as his propulsion into the "big time". No amount of questioning by a journalist, no matter how dogged and free, is able to prevent that and it is in the public interest to ensure such things are prevented.