As many as eighty percent of rape complainants in some police force areas are being asked to give up personal information from their mobile phones, new figures show.

Those reporting rape, including children, are regularly being asked to divulge all of their mobile phone data Rape Crisis England and Wales have revealed after surveying their frontline staff. 

The findings raise serious questions about the proportionality of requests for personal information in rape investigations and prosecutions.

Fewer than 20% of rapes, sexual assaults, and instances of sexual abuse are thought to be reported, and last week it was revealed that just 3.3% of all reported rapes ended in conviction. 

Figures collected for The Guardian by Rape Crisis England and Wales revealed that all frontline staff had been in contact with clients who had been asked for a large amount of personal information, with 86% saying it was now standard practice. 

More than half of workers said more than half of complainants (53%) were told that their cases might not be able to proceed without the data, requests which workers said in almost all cases (95%) had a negative impact on complainants and had seen it deterring people from coming forward. 

More than 60% of workers also said that requests were being made in some rape cases involving a stranger, with the information gathered from phones deemed to be “disproportionate” in some cases, with details about the complainants’ “previous sexual history” and “lifestyle” scrutinised. 

Katie Russell, spokesperson for Rape Crisis England & Wales said the data proved what independent sexual violence advocates across the organisation’s network had been reporting “for some time” – that full downloads of mobile data were “becoming increasingly common, even routine.” 

She said: “Victims and survivors too often tell us they end up feeling like the ones under investigation, especially when their rapist is rarely subjected to the same intensive level of scrutiny or invasion of privacy.

“There’s no doubt this practice already contributes to high rates of victims and survivors dropping out of the criminal justice process after reporting, and puts others still off reporting to the police altogether. This situation will only continue unless this practice is urgently reviewed and reformed.

“When less than 20% of those who are raped, sexually assaulted or sexually abused currently report to the police, and when the criminal justice system is so badly failing the majority of those who do, this treatment of victims and survivors is not justified, proportionate, in the interests of justice or acceptable.”