LONDON • Britain has handed to the US authorities evidence related to two members of an Islamic State in Iraq and Syria (ISIS) murder cell dubbed the "Beatles", clearing the way to a trial after Washington said it would not seek the death penalty for the duo.

The evidence regarding El Shafee Elsheikh and Alexanda Kotey "has now finally been transferred to the US", British Home Secretary Priti Patel said on Twitter on Tuesday. "I sincerely hope that justice for the victims and their families will now be served," she said.

Elsheikh and Kotey, who have been stripped of their British citizenship, are in the custody of US forces in Iraq. The United States wants to try them for the murder of journalists James Foley and Steven Sotloff, and aid worker Peter Kassig between 2014 and 2015.

The duo's four-member cell was dubbed "the Beatles" by their captives due to their English accents. They tortured and killed victims, including by beheading, and ISIS released videos of the deaths for propaganda purposes.

The transfer of material intended to help the pair's prosecution came after Elsheikh's mother lost a legal challenge in London's High Court.

Ms Maha Elgizouli's lawyers had told the court that Ms Patel's decision to press on with the transfer breached Britain's Data Protection Act. But the judges ruled that the Home Secretary was within her rights.

"The conclusion that, even if Mr Elsheikh could be prosecuted in England, it would still be necessary and proportionate to transfer the data to the US authorities remained a conclusion properly open to the Secretary of State," the ruling said.

Relatives of two Britons who had been killed by the ISIS cell welcomed the breakthrough yesterday.

The families of Mr Alan Henning and Mr David Haines said the ruling permitting the British government to share evidence with the US authorities about the suspects was a "huge result for us".

"We have only ever wanted to see these two men being held accountable and brought to justice through a fair trial for their alleged actions," they said in a statement released by the charity Hostage International.

A two-year legal impasse concerning the suspects was broken last month when US Attorney-General Bill Barr said they would be spared execution if convicted after trial in the US.

But he also warned that unless the British evidence was shared by Oct 15, Kotey and Elsheikh would be handed over for prosecution and possible execution in Iraq.

Mr Barr's intervention put the onus on Ms Patel to see if the British system could overcome the court challenge by Elsheikh's mother and share the evidence - said to be damning wiretaps - with the US authorities.

The US Department of Justice welcomed Tuesday's court ruling in London and expressed gratitude to Britain for transferring the evidence.

"We remain committed to holding these defendants accountable and obtaining justice for the victims of their terrorist activity," it said in a statement.

AGENCE FRANCE-PRESSE