The President of the European Court of Human Rights has expressed his disappointment in the British Government's criticisms of its work.
Sir Nicolas Bratza, writing in The Independent, said it would be "deeply regrettable" if the UK's support of the European Convention of Human Rights, which is enforced by the Strasbourg court, was to be called into question.
David Cameron will make a speech on what Downing Street described as the "much-needed reform" of the court when he travels to Strasbourg on Wednesday.
His visit comes amid anger among Conservatives at the court's ruling that Britain could not deport the radical Islamist cleric Abu Qatada to stand trial on terrorism charges in his native Jordan. The Government has also been in debate with the court over the issue of prisoners' voting rights.
Sir Nicolas maintained that there are reasons for optimism, and that solutions were being sought to the problem of the backlog. He said: "Against this background, it is disappointing to hear senior British politicians lending their voices to criticisms more frequently heard in the popular press, often based on a misunderstanding of the court's role and history, and of the legal issues at stake."
One of the key criticisms, that the court unnecessarily interferes in domestic cases, is "simply not borne out by the facts", Sir Nicolas said. The other concern, about the backlog of cases, is not linked to inefficiency but is a result of an increase in the number of states signing up to the ECHR, according to the judge.
Sir Nicolas added: "It is particularly unfortunate that a single judgment of the court on a case relating to UK prisoners' voting rights, which was delivered in 2005 and has still not been implemented, has been used as the springboard for a sustained attack on the court and has led to repeated calls for the granting of powers of Parliament to override judgments of the court against the UK, and even for the withdrawal of the UK from the convention."
Sir Nicolas said the influence of the Strasbourg Court on the UK has been "overwhelmingly positive", but added: "It would, however, be surprising if all its decisions were popular with the government of the day, or indeed understood and accepted by public opinion".
He highlighted the successes of the court, including making sure children are not tried in adult courts and the legal recognition of transsexuals, and said that the UK's contribution to the convention had been "immense".
A Downing Street spokeswoman said: "The Government's position on this issue is a matter of record and has not changed. We believe the court is an essential part of the system for protecting human rights across Europe but it is not working as well as it could and it is in need of fundamental reform... Our top priority during our Chairmanship of the Council of Europe is to agree a robust package of reform. We want the court to fulfil the purpose for which it was intended - to uphold human rights under the Convention and to tackle serious violations of human rights across Europe."