Victims of crimes, including those alleging rape, are to be asked to hand their phones over to police - or risk prosecutions not going ahead.
Consent forms asking for permission to access information including emails, messages and photographs have been rolled out in England and Wales.
It comes after a number of rape and serious sexual assault cases collapsed after crucial evidence emerged.
Victim Support said the move could stop victims from coming forward.
But police and prosecutors say the forms are an attempt to plug a gap in the law which says complainants and witnesses cannot be forced to disclose phones, laptops, tablets or smart watches.
Director of Public Prosecutions Max Hill said they would only be looked at where it forms a "reasonable line of enquiry", with only relevant material going before a court if it meets stringent rules.
The digital consent forms can be used for complainants in any criminal investigations but are most likely to be used in rape and sexual assault cases, where complainants often know the suspect.
The forms state that victims will be given the chance to explain why they don't want to give consent for police to access data, but they are also told: "If you refuse permission for the police to investigate, or for the prosecution to disclose material which would enable the defendant to have a fair trial then it may not be possible for the investigation or prosecution to continue."
Asking victims, complainants and witnesses - including those alleging rape - to consent to having their smartphones and mobile devices examined is a big ask.
Most modern phones have more computing power than that which powered the first Nasa missions.
They contain photographs (sometimes intimate), emails and social media postings - (sometimes deeply personal, sometimes indiscreet) - not to mention text messages written in haste.
Many people guard the contents of their smartphones jealously and would regard a police examination as an invasion of privacy.
Civil liberties groups have raised concerns that victims may not report crimes if they fear their smartphone will need to be examined.
However, the police do not have the power simply to seize the phones of victims and witnesses, so consent is the only option. Will people willingly hand over their devices? Would you?
https://www.bbc.co.uk/news/uk-48086244
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This is very serious, and a major step backward I think