Alleged sex abuse victims are having their sexual history used against them in court
Northumbria Police and Crime Commissioner Dame Vera Baird said she was concerned by her analysis of 30 rape trials at Newcastle Crown Court.
In 11 cases, complainants' sexual history was brought up – in seven cases without the proper procedure being followed.
The former Labour MP said: "In two trials, defence barristers put previous sexual history before the jury, never having made an application for leave to do so, nor obtained leave.
"In a third trial, the defendant did so without being stopped either by the prosecution or the judge.
"In four other trials, observers noted that previous sexual conduct was used to discredit the complainant – this seemed to be express – but was not relevant to any other issue, whereas Section 41 says that it should be used to if its main purpose is impugn her credibility, even if it may be relevant to an issue.
"The legislation in these trials did not seem to work well."
Dame Vera Baird has called for changes within the trial process
Her new report says that in one case, the defence barrister said he had brought the alleged victim's sexual history up to show that "she is an adulteress".
Sexual conduct was used to discredit the complainant
Dame Vera Baird
It adds that while judges are reluctant to refuse to hear late applications in case they are relevant to the case, the effect "is to ambush the complainant and the prosecution" with details of the complainant's sexual history.
"We do have concerns about section 41 evidence and will send the results to the Secretary of State's current enquiry into the admission of previous sexual history in rape trials," Dame Vera said.
A ban on such questioning is one of the options being looked at in a review by Ministry of Justice officials.
In 11 of 30 Newcastle rape trials, the victims sexual history was brought up
Plaid Cymru MP Liz Saville Roberts has also introduced a Private Member's Bill aimed at preventing the cross-examination of alleged rape victims about their sexual history, behaviour or appearance.
Campaigners believe the Ched Evans case has led to a rise in the number of defendants successfully applying to have the sexual history of their alleged victims used as evidence under section 41 of the Youth Justice and Criminal Evidence Act 1999.
The Welsh footballer was acquitted of raping a 19-year-old woman at a retrial after a judge controversially allowed evidence from two men who had sex with her around the time of the allegation to be heard.
In one case the victim's sexual history was raised to show 'she was an adulteress'
Dame Vera's report comes after 12 independent observers watched the 30 trials between January 2015 and June last year.
Of the 25 cases that were finally resolved, with five being re-tried, just six resulted in guilty verdicts.
Dame Vera believes small changes to the trial process could lead to a higher rate of convictions, including ensuring evidence of previous sexual conduct is not introduced into the proceedings without proper applications.