What happens when the ECHR conflicts with international law?

Analysis

Public Law analysis: How can the UK have jurisdiction over an individual who has been transferred to US custody following admission to a military camp? Robert G Volterra, of Volterra Fietta, discusses a ruling in the European Court of Human Rights (ECtHR), which found that the UK retained authority over all aspects of the detention and did not breach the European Convention on Human Rights, art 5 (ECHR).

Original news

Hassan v United Kingdom (App No 29750/09) [2014] ECHR 29750/09, [2014] All ER (D) 116 (Sep)

Following his brother's death after having been detained by UK armed forces in Iraq, the applicant lodged an application against the UK, alleging, among other things, breaches of ECHR, art 5. The ECtHR, in dismissing the application, held that, although the brother had fallen within the jurisdiction of the UK, his detention had not been arbitrary and there had been no violation of ECHR, art 5.

What is the significance of this decision?