The number of sexual abuse victims calling charity helplines has increased in the wake of the Jimmy Savile scandal, the charities say.
Coverage of Savile's campaign of abuse has prompted people to report other abuse going back many years, they say.
The National Association for People Abused in Childhood (Napac) says it has had 2,500 calls in three weeks. It usually receives 200 to 300 a week.
Police are investigating complaints of sexual abuse by the late entertainer.
It is believed the television presenter and DJ may have abused many people - including young girls - over a 40-year period.
As well as receiving 161 calls relating to allegations against Savile, details of which have been passed to police, the NSPCC says it has also received 105 contacts from adults wishing to talk about unrelated abuse suffered as children.
Charities say the Savile scandal has given people the courage to come forward about sexual abuse.
Peter Saunders from the National Association for People Abused in Childhood (Napac) said: "We've seen an unprecedented deluge of callers, people making contact with us, survivors of abuse telling us about stuff that's happened to them, mostly a long time ago.
"It's been a period of just unprecedented numbers to our charity."
The Lucy Faithfull Foundation child protection charity has seen a 50% increase in call volumes.
Rape Crisis centres say they have seen a 20% increase in callers, with one centre getting as many callers in a day as they usually get in a week.
Jo Wood, from Rape Crisis, said: "This has spiked at times of mass media coverage of the Jimmy Savile story. In the week following the initial Exposure documentary, centres were reporting being overwhelmed by callers and an increase over several days of 80%.
"It is difficult to give actual figures as each centre maintains their own records - however, one centre in Merseyside is currently receiving one to two new callers per day where previously they were getting two to three per week."
As well as charities, lawyers say they have been getting more approaches from people alleging abuse.
Pannone, a firm of solicitors which specialises in helping victims of sex abuse, says it has seen a five-fold increase in people coming forward.
Alan Collins from the firm said: "The depth of coverage and the quality of the coverage empowers them because they're being exposed to people who have knowledge of how to progress a child abuse case.
"In my opinion that enables the victims to say, 'Yes, if I now step forward and take that step of reporting what happened to me, it will be taken seriously - I'm not going to be ridiculed, I'm not going to be dismissed.'"
The Metropolitan Police has launched a criminal investigation into the allegations against Savile.
It said it was following up 400 lines of inquiry, with more than 200 potential victims having been identified. Scotland Yard is also in contact with 14 other police forces.