MONITORING PLACES OF DETENTION : A PRACTICAL GUIDE 46 3.2 National preventive mechanisms under the OPCAT The standards and criteria set out in the OPCAT are of particular relevance for domestic visiting mechanisms which might be designated “national preventive mechanisms”. They are also of interest to other domestic visiting bodies, since they represent the ’state of the art’ in international reflection on the guarantees needed to ensure that domestic visiting mechanisms are effective. 3.2.1 Setting up or designation of national preventive mechanisms States Parties have an obligation to “maintain, designate or establish (…) one or several independent national preventive mechanisms for the prevention of torture at the domestic level” (Art. 17) 10. Accordingly, some States will need to create a new body, whilst others that may already have such a mechanism will need to consider whether it fully complies with the obligations under the Optional Protocol. In order to help States Parties to set up effective national mechanisms, the Sub-Committee can provide assistance and advice. Therefore, the Sub-Committee has the mandate to advise States Parties on the establishment of national mechanisms. The SubCommittee can also offer direct assistance and training to national preventive mechanisms. When a State designates an existing body as the “national preventive mechanism” under the OPCAT, it has to assess that it fulfils the criteria defined in the Optional Protocol, particularly regarding functional independence. The Sub-Committee will also be able to look at the effective functioning of the national preventive mechanism. It 10 States Parties are obliged to have national preventive mechanisms in place within one year of entry into force of the OPCAT or, once it is in force, upon ratifying the OPCAT. However, States may make a declaration upon ratification under Article 24 to temporarily postpone their obligations in respect of the national mechanisms for a maximum period of five years.