Commissioner of Police of the Metropolis (Appellant) v DSD and another (Respondents)

This case involved a claim by two victims of sexual offences committed by a serial offender, John Worboys, who was a black cab driver in London. The victims claimed that the police had failed to conduct an effective investigation into their respective cases, which amounted to a breach of article 3 of the European Convention on Human Rights (ECHR). They argued that this failure constituted a violation of their rights under the ECHR, which was actionable under the Human Rights Act 1998 (HRA). The primary legal issue before the Supreme Court was the nature and scope of the duty owed by the state to investigate serious criminal offences under article 3 of the ECHR. The appellant argued that the duty was a public one, owed to the public at large, and not to individual victims. The respondents, on the other hand, argued that the duty was a protective one, owed to individuals, and that failure to fulfil this duty gave rise to a right to claim compensation against the state. The Supreme Court held that the state had a duty under article 3 to conduct an effective investigation into crimes which involve serious violence to an individual, whether committed by state agents or individual criminals. The court found that the European Court of Human Rights (ECtHR) had consistently held that the state had a positive obligation to investigate allegations of ill-treatment, even if the perpetrators were not state agents. The court also held that compensation was not automatically payable for breaches of the article 3 duty to investigate and prosecute crime, but the award of compensation served to uphold minimum human rights standards and to vindicate those rights. The Supreme Court further held that the fact that there was no common law duty of care on the police did not affect the existence of the duty under the ECHR. The court rejected the argument that the exemption from liability of the police at common law should be extended to claims under the HRA. Finally, the court held that the question of the nature and scope of the duty to investigate under article 3 should not be left to the ECtHR, but should be determined by domestic courts, in accordance with the principles of the ECHR and the HRA.