The invasion of Iraq by the UK and US in March 2003 led to hundreds of thousands of egregious human rights violations by the UK: unlawful deaths, acts of torture or arbitrary detention without charge. The UK government has deployed a range of legal arguments to escape accountability for such violations.

On 7 July, the Grand Chamber of the European Court of Human Rights (ECtHR) handed down two judgments (Al-Skeini and Others v UK and Al-Jedda v UK) whose combined effect is to destroy four of its key arguments.

The first is staggering in its potential adverse consequences. In both cases, the UK argued that, despite invading without a UN authorisation, all the acts of UK personnel from October 2003 were attributable to the UN, not the UK. This, despite the fact that the UK and US had sought and obtained an authorisation from the UN to administer all of Iraq as joint occupying powers and as co-architects of the Coalition Provisional Authority that exercised all the public powers of the Iraqi central and local state (UN Security Council Resolution (UNSCR) 1483, 22 May 2003).

The UK argued that from 16 October 2003 (when UNSCR 1511 authorised the multinational force in Iraq to take all necessary measures to ‘contribute to the maintenance of security and stability in Iraq’) all UK actions were attributable to the UN. Thus, if Baha Mousa had been tortured to death by UK troops a month later his family would have had no remedy.

In Al-Skeini, the ECtHR said the UK were estopped from raising the argument as they had not done so in the domestic courts. In Al-Jedda, the court found that at all times the actions of the UK personnel were attributable to the UK. If it had been otherwise no question of European Convention on Human Rights (ECHR) jurisdiction could have arisen.

The UK government had fought and lost the argument in the House of Lords that the Human Rights Act 1998 applied only to the territory of the UK. The Lords had found, though, that the reach of the ECHR was narrow. Mousa, killed in a UK detention facility analogous to an embassy, was within ECHR jurisdiction. All other cases of unlawful killings raised were not.

The ECtHR found that all the cases were within the UK’s jurisdiction in a manner that will resound far and wide. It confirmed two different circumstances where there will be ECHR jurisdiction anywhere in the world. First, when agents of a state have authority and control over others, for example an arrest or house raid.

Second, when a state has control of an area ‘as a consequence of lawful or unlawful military action’. Thus, as the UK had been exercising ‘public powers’ and/or been ‘engaged in security operations’ in these deaths there was a ‘jurisdictional link’ between the UK and the deceased.

In Al-Skeini, the UK argued that, even if there was jurisdiction, the duty to investigate independently, promptly and effectively that protects articles 2 and 3 of the ECHR had been met by the military justice system. This involves soldiers investigating other soldiers. Not good enough said the court.

In Al-Jedda, the UK argued that the UNSCR could displace domestically the right not to be arbitrarily detained. The effect of an exchange of letters between the US and the Iraqi interim government, referred to in UNSCR 1546, created an obligation for the UK to intern the applicant without charge for 38 months from October 2004.

The court found no such obligation had been created, particularly in circumstances where the UN itself had repeatedly complained about mass internment of Iraqis in this period.

The UK must now atone for its sins by holding inquiries into all deaths and acts of torture in Iraq for which it is responsible.

Phil Shiner, a solicitor at Public Interest Lawyers, acts for the families of Iraqi civilians killed or wrongfully detained by British troops in Basra