MONITORING PLACES OF DETENTION : A PRACTICAL GUIDE 47 can make recommendations to the State Party with a view to strengthening its capacity and mandate to prevent torture and ill-treatment. It should also be underlined that the designation or setting-up of a national preventive mechanism should not be used by States to undercut visiting activities carried out by other domestic bodies, in particular by non-governmental organisations. Monitoring activities by different actors should be considered as complementary in the prevention of torture. 3.2.2 Form of national preventive mechanisms The OPCAT does not prescribe any particular form that national preventive mechanisms must take. States Parties therefore have the flexibility to choose the type of body that is most appropriate to their particular country context. A national preventive mechanism could be a national human rights institution, an Ombudsman, a parliamentary commission, an NGO, a lay people scheme, or any specialised body set up specifically to monitor places of detention. States Parties can decide to have several national preventive mechanisms because of the State structure (for example, federalism) or based on a thematic division. When a State decides to have several national preventive mechanisms, be they regional or thematic, it would be advisable to find a means to achieve cooperation between the different bodies, for example by having one coordinating body at the national level that works to harmonise the contribution of each visiting body. 3.2.3 Mandate of national preventive mechanisms The preventive effect of visits to places of detention depends on the regularity of those visits and on the follow-up to those visits. Therefore the national preventive mechanisms are mandated to conduct regular visits to all places where people are deprived of their liberty and to make recommendations.