A US trial of two members of Islamic State accused of taking part in the beheading of hostages appears likely to go ahead, following a legal ruling that allows the UK to share evidence with US prosecutors. Britain’s supreme court said on Wednesday that a stay preventing the Home Office from supplying intelligence relating to Alexanda Kotey and El Shafee Elsheikh must be lifted after the US said it would drop death penalty charges against them. The Home Office said it would not comment on what it would do next, but the UK is expected to share evidence that US prosecutors have said they believe is vital for a trial to take place. There may, however, be a last-minute legal challenge to try to prevent the two countries from cooperating. Kotey, 36, and Elsheikh, 32, two members of a notorious gang of four Britons that hostages nicknamed “the Beatles”, left the UK to join Isis soon after it emerged in Syria and Iraq. They have been accused of involvement in the gruesome killings of four US citizens and two Britons, which were filmed and broadcast online six years ago. The victims were the British aid workers David Haines and Alan Henning, the US journalists James Foley and Steven Sotloff, and the US aid workers Peter Kassig and Kayla Mueller, who was also tortured and sexually abused. Families representing the victims have campaigned for the two men to be put on trial in the US, urging the authorities to drop the death penalty charge so that Britain can cooperate fully with them. Sotloff’s father, Art, told NBC News he was pleased “our governments are finally working with each other”. Mueller’s parents are due to address the Republican convention on Thursday evening. The US attorney general, William Barr, wrote to the British home secretary, Priti Patel, last week to confirm that his country would not pursue the death penalty in return for British cooperation before a deadline of 15 October. “Further delay is no longer possible if Kotey and Elsheikh are to be tried in the United States, and the further delay is an injustice to the families of the victims,” Barr wrote. The Home Office said at the time that it welcomed the development and that it continued to work closely with its international partners to ensure that those who have committed crimes in the name of Isis were brought to justice. The two men are being held in Iraq for several months after the US military removed them from Syria, where Kurdish forces had been holding them. Barr had said that if the UK did not assist by 15 October, Washington would hand the pair over to the Iraqi judicial system instead. The UK does not normally cooperate with prosecutions brought by other countries if the death penalty is a possibility, although in 2018 the then home secretary Sajid Javid said he was willing to waive the requirement in the case of the two men. The supreme court, however, ruled in March that his actions had been unlawful following an appeal from Elsheikh’s mother, Maha Elgizouli. Her lawyers had argued the two should be put on trial in the UK instead, something the British authorities refused to do. Both Kotey and Elsheikh were stripped of their British citizenship in 2018. The most infamous member of the Beatles cell was Mohammed Emwazi, who was killed in a US drone strike in 2015. A fourth member, Aine Davis, is in prison in Turkey after being jailed for seven years in 2017 for serving Isis.