Police are asking rape and sexual assault victims for access to their digital devices under new guidelines published on Monday that prompted criticism from women's rights campaigners in Britain.
Officers now present victims with consent forms to view messages, photographs, emails and social media accounts, with police warning that prosecutions may not go ahead without the permissions.
The change follows a disclosure scandal in the legal system which saw a series of rape and sexual assault cases collapse in recent years after crucial evidence emerged at the last minute.
Assistant commissioner Nick Ephgrave, of the National Police Chiefs' Council, said the new "informed consent" forms would be used "proportionately and consistently".
He added police were working with victim groups and others to ensure the approach had "the necessary balance".
"We would never want victims to feel that they can't report crimes because of 'intrusion' in their data," Ephgrave said in a statement.
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But women's advocates as well as privacy campaigners have hit out at the consent forms as overly intrusive and argue they could deter people from reporting crimes.
"We seem to be going back to the bad old days when victims of rape are being treated as suspects," said Harriet Wistrich, director of the Centre for Women's Justice.
The organisation said it was preparing a legal challenge to the policy alongside privacy advocates Big Brother Watch, which has dubbed the measures "digital strip searches".
Prime Minister Theresa May's spokesman said Monday that the issue was "complex" and police would conduct impact assessments on the forms.
"While disclosure is an important component of the criminal justice system... the police have acknowledged that the use of personal data in criminal investigations is a source of anxiety," he said.
"We want victims to have the confidence to come forward." The forms are part of a wholesale review of disclosure processes within the legal system in England and Wales.
It has included providing updated disclosure training to all prosecutors and more than 93,000 police officers and staff.