E/CN.4/1991/17 page 92 consideration of the draft optional protocol to its forty-seventh session since it thought it advisable to take note, on the one hand, of the experience of the European Convention for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment, which had entered into force on 1 February 1988, and, on the other hand, of the work being carried out in other regions designed to establish regional systems of visits to places of detention (decision 1989/104). 297. The Commission will therefore resume consideration of the draft optional protocol at its present session. The Special Rapporteur has been informed that the first report of the Committee established under the European Convention will be published in the beginning of 1991. The Special Rapporteur has also been informed that in other regions no steps have been taken to establish similar regional systems of visits. 298. As the Special Rapporteur said in previous reports, such systems of periodic visits must be deemed to be one of the most effective preventive measures against torture. As a result of such visits by a committee of experts Governments may be advised on measures to be taken to improve the existing regime in places of detention or imprisonment. The element of periodicity is designed to strengthen its preventive effect and to emphasize its character as a form of co-operation with the Government concerned, which is also underlined by the confidentiality of the reporting system. Although the institution of such systems of visits on the national level must be welcomed and consequently has been recommended by the Special Rapporteur, the preventive effects of an international system will be incomparably stronger. 299. As the Special Rapporteur stated in his second report (E/CN.4/1987/13, para. 8 5 ) , such a system of visits is no more an intrusion in the domestic jurisdiction of a State than the visits of staff members of the International Atomic Energy Agency to nuclear facilities which may also lead to recommendations for the improvement of existing standards. Just as in the latter case such visits have been accepted since they serve a purpose which is recognized by the international community as being of vital importance, namely the maintenance of international peace and security, a system of visits to places of detention would serve the purpose of ensuring respect for human dignity, a value deemed by the international community of equivalent importance. 300. The introduction of a system, as provided for by the draft optional protocol, would to a certain extent be the final stone in the edifice which the United Nations has built in their campaign against torture. It would also reflect the three-tiered system of activities of the United Nations in the field of human rights. First, torture was explicitly prohibited, (standard-setting). Secondly, a convention was concluded to strengthen the standard. The Parties to the Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment have committed themselves to take measures on the national level which will enable them better to implement the norm (implementation). Adoption of the draft optional protocol would constitute an illustration of the most recent branch of United Nations activities: co-operation between individual Governments and the international community for the promotion of the respect for human rights (Advisory Services).