Deprivation of liberty Page 63 Conclusion The most intrusive interference with an individual’s liberty is most likely to involve a deprivation of liberty. That a deprivation of liberty may be necessary to assist in the investigation of crime or for the protection of the public and of the individual himself is self-evident, but legitimate State interests cannot be used to justify untrammelled police authority. Guarantees against the use of arbitrary deprivation of liberty are contained in Article 5, and while the case law generated by this provision in part reflects the wide variety of systems of criminal justice found throughout the continent, the underlying principles in this jurisprudence exhibit consistency in stressing the need to ensure that loss of liberty in each instance is lawful, seeks to achieve a permissible end, and is not prolonged any more than is necessary. Deprivation of liberty should only be used where this is justified by the circumstances, and detention which has ceased to be justified must result in the release of the individual. This care to minimise the risk of unwarranted and prolonged deprivations of liberty complements the protection accorded by other guarantees, most noticeably Article 3 in respect of the risk of ill-treatment during detention. Both the risk of ill-treatment and the risk of unwarranted deprivation of liberty are of particular relevance to persons detained on suspicion of commission of an offence. This consequently gives rise to concerns affecting the investigation of crime by police officers, and it is to this subject that attention now logically turns.
The European Convention on Human Rights and Policing Page 64 Chapter 4 Investigating crime; and ensuring the integrity of the criminal process Introduction Police officers are likely to play the key role in the task of investigating allegations of criminal behaviour. Whether they do so under the general supervision or the specific guidance of a prosecutor or of a judge, or in their own right, the level of involvement of police officers in the initial stages of a criminal process is likely to be considerable. To this end, domestic law will confer considerable authority upon police officers to interrogate suspects and witnesses, to carry out searches, to undertake surveillance, and generally to secure evidence. Many of these powers may be highly intrusive, particularly the powers to detain a suspect and to search for real evidence. In certain circumstances, however, the police are under a particular responsibility to intervene in order to protect the rights of others, and the failure to take appropriate action may indeed constitute a violation of the European Convention on Human Rights. Much of this chapter seeks to analyse the key considerations for police officers in ensuring the integrity of the criminal process while investigating allegations of crime. Investigation may thus give rise to a number of issues under the European Convention on Human Rights. Most obviously, the deprivation of liberty of a person reasonably suspected of committing an offence will give rise to the compatibility of the detention with Article 5 (as discussed in chapter 3). However, other guarantees under the Convention are also relevant. In particular, Article 8 is likely to be engaged whenever a search or surveillance takes place as this will involve an interference with respect for private life, home and correspondence. Interrogation of suspects which involves the infliction or threat of infliction of ill-treatment may also give rise to issues under Article 3 (as discussed in chapter 2). But these aspects of police investigation practices also have another dimension, as they take place within the context of a criminal process and may also have an important impact upon the fairness of a criminal trial under Article 6.