The media can be more critical of politicians than of private individuals, and be protected by the European Court of Human Rights, according to its president, Prof Luzius Wildhaber.

Judge Wildhaber was speaking at the "Broadcasting, Society and the Law" lecture in UCD last night, on the subject "The right to offend, shock or disturb - aspects of freedom of expression under the European Convention on Human Rights".

Describing the case-law that had developed in the Strasbourg court over the years, Prof Wildhaber said: "A politician inevitably and knowingly lays himself open to close scrutiny of his every word and deed."

A number of the cases concerning the right to criticise politicians involved Austria, where the court found that a comment or value-judgment was not susceptible to proof.

If the facts on which these value judgments were based were undisputed then the journalist was entitled to the protection of Article 10 of the European Convention on Human Rights, which guarantees freedom of speech.

However, this latitude did not extend to discussing aspects of the private lives of members of politicians' families.

In an Estonian case the court found that the public status of a politician's wife was not enough to justify a criticism of her private life, and upheld a conviction for insulting the woman.

"This case does, if somewhat timidly, set some limits on the operation of freedom of expression in respect of the private life of public figures. It is not every person who has been in the public eye whose private life can be regarded as a matter of public concern," Judge Wildhaber said.

The court had been more restrictive in relation to criticism of members of the judiciary.

"The judiciary had to enjoy public confidence and it might prove necessary to protect such confidence against destructive attacks that were essentially unfounded, particularly in view of the fact that judges were subject to a duty of discretion which prevented them from replying."

The court had also upheld the right to criticise the state itself, notably in a number of judgments relating to Turkey.

"In a democratic system the actions or omissions of the government must be subject to the close scrutiny not only of the legislative and judicial authorities, but also of public opinion," said Judge Wildhaber.

However, the court has given a wide degree of discretion to national governments to decide what restrictions can be imposed on freedom of expression for moral reasons.

While artistic expression comes within the ambit of Article 10, the court noted: "It was not possible to find in the legal and social orders of the contracting states a uniform conception of morals."

In a number of cases involving public morals, therefore, the decisions of national courts were upheld by the European Court of Human Rights.