-71 ‘‘The NPMs focus on vulnerability in detention should become an integral part of their work’’ 4.CONCLUSION Since their establishment, a number of national preventive mechanisms in Europe have embarked into monitoring the rights of detainees in a situation of vulnerability. Their approaches vary – while some have focused on specific groups and undertaken substantial monitoring work and produced special reports, others have included this theme in their general monitoring work and reports. Still others have not yet dealt with the issue in any way. The NPM focus on vulnerability in detention should become an integral part of their work, as it constitutes an essential aspect of their mandate to prevent torture, inhuman and degrading treatment. The standards for treatment of vulnerable groups in detention at the international level are incoherent. The UN and CoE bodies have produced elaborate standards for some, but have paid little or no attention to other vulnerable groups. The EU has not developed its own comprehensive standards on deprivation of liberty or on the situation of vulnerable groups. This is a weakness of EU law, which, along with some serious discrepancies between the existing international standards and the situation in a number of member states, prevents mutual trust and judicial cooperation in general. Some NPMs have tried to determine vulnerability in detention in accordance with the specific circumstances of their national context. This is a healthy approach that should be encouraged. Although monitoring the rights of groups and individuals in a situation of vulnerability has a long history in Europe, NPMs need to further develop approaches and skills in this regard and expand their reach to groups that have not received sufficient attention so far. NPMs are in a good position to benefit from the strengths of both official and non-governmental monitoring approaches, as well as from a combination of qualitative and quantitative methods in their monitoring work. Prisoners in a Situation of Vulnerability