Rape victims are showing signs of increased confidence in the criminal justice system, a leading charity has said, as official figures showed a rise in the number of sexual offences reported to the police.
Sexual offences recorded by the police rose 9% to 55,812 in the year to June 2013, which the Office for National Statistics (ONS) partly put down to publicity around the Jimmy Savile scandal.
Rape Crisis England & Wales said this so-called "Yewtree effect", named after the police investigation prompted by the Savile disclosures, partly reflects victims' greater confidence in the treatment they will receive if they come forward.
But the charity's spokeswoman Katie Russell also said sexual offences have long been under-reported with just 15% of the estimated 95,000 women and men who are raped and nearly 500,000 who are sexually assaulted in England and Wales every year currently choosing to go to the police.
She said: " Through our frontline experience of providing specialist services to women and girls affected by sexual violence, we know that among the many and complex reasons for under-reporting is a fear of not being believed.
"The increased media and public interest in sexual violence and survivors' stories in the wake of the Jimmy Savile revelations does seem to have prompted some survivors to come forward, often for the first time after years or even decades, and this must at least partly reflect an increased confidence in the treatment they can expect to receive from the criminal justice system."
The Rape Crisis National Helpline has seen a 40% increase in calls during the year since the documentary exposing Savile was first broadcast.
In all, there were nearly 1,400 more rapes in the year reported to police compared with the previous year, plus 3,100 other sex offences.
Tony Lloyd, chairman of the Association of Police and Crime Commissioners (PCC) Board and PCC for Greater Manchester, said: "I am concerned however about the increase in sexual offences.
"Although some of the recorded increase is related to historical cases this is a worrying trend which must be addressed. There is also a need to offer greater support to the victims of sexual offences.
"Police and Crime Commissioners are very supportive of their local Sexual Assault Referral Centres and other local support services which continue to play an important role in supporting victims."
Shadow policing minister Jack Dromey said changes to the national DNA database brought in by the coalition government, under which DNA profiles from people arrested but not charged with a serious offence are being destroyed, are making it harder to tackle sexual offences.
He said: "The significant increase in sexual offences must of course be seen in the context of Operation Yewtree but, as the Office for National Statistics states, this is thought to only partly explain the rise.
"The Government should be working with forces to tackle this crime, instead of making it harder by destroying DNA."
Elsewhere, the ONS figures showed a 7% fall in overall crime against households and adults in England and Wales.
There were about 8.5 million incidents of crime against households and adults, according to the Crime Survey for England and Wales (CSEW), compared with 9.1 million in the year to June 2012.
The headline crime figure is the lowest since the survey began in 1981 , and is now less than half its peak level in 1995.
The police recorded 3.7 million offences in the year to June, a decrease of 5% compared with the previous year.
There were 230,335 fraud offences recorded in the same period - a 21% increase compared with the previous year.
But the ONS said the figures should be viewed in the context of a move towards the centralised recording of fraud by police.
There were also increases in theft from the person, which was up 8%, and shoplifting, up 1%.
Crime prevention minister Norman Baker said: " Police reform is working and crime is falling.
"Recorded crime has dropped yet again, by more than 10% under the coalition Government, and the crime survey says that crime has more than halved since its peak in 1995.
"This is really positive news. Forces are rising to the challenge of making savings whilst cutting crime and delivering a better service to the public.
"England and Wales are safer than they have been for decades bu t we will continue to deliver measures which keep pace with the changing nature of crime and improve our ability to combat emerging issues."