4 Exhaustive list of grounds for detention This chapter analyses allowed grounds for detention, focusing on European law (Figure 7). The international (UN) instruments do not list grounds for detention, but require that deprivation of liberty be based on grounds established by law (see Table 3). European law, in contrast, contains an exhaustive list of grounds for detention. They make no distinction between adults and children. Under the ECHR, no detention that is arbitrary can be compatible with Article 5 (1). To avoid being branded as arbitrary, detention under Article 5 (1) (f) must fulfil a number of conditions, one of which is that it must be closely connected to the ground of detention relied upon.128 Figure 7: Five conditions that deprivation of liberty must meet not to be unlawful and arbitrary Fundamental rights safeguards Clear legal basis in national law BASED ON ALLOWED GROUNDS Necessary and proportionate Respects procedural safeguards Conditions are humane and dignified Source: FRA, 2017 128 ECtHR, A. and Others v. United Kingdom [GC], No. 3455/05, 19 February 2009, para. 164; Thimothawes v. Belgium, No. 39061/11, 4 April 2017, para. 64. 41